Bali belly is the single most common reason a guest cancels a dive day with us, and it beats weather, flights and hangovers combined. We run our dive centre in Sanur and we deal with some version of this most weeks: a message at half past five in the morning, someone who has been up all night, asking whether they should still come. This guide is the answer we give, written out properly. What it is, how to not get it, what to take when you do, what treatment actually costs here, and the part nobody else covers, which is when it is safe to get back in the water.
That last part matters more than people expect. Dehydration is a recognised risk factor for decompression sickness, so a stomach bug is not just an inconvenient day, it changes the risk of the dive itself. If you are booked on a Nusa Penida diving day trip from Bali and you were up four times in the night, the honest advice is to move the booking rather than tough it out. We will move it. It costs you nothing and it costs us very little.
Bali belly is traveller's diarrhoea, an infection you swallow, most often the bacterium enterotoxigenic E. coli. It is not your stomach adjusting to spice.
- How long it lasts: 3 to 7 days untreated if bacterial, 2 to 3 if viral. Weeks if it is giardia.
- What to take: oral rehydration salts, sold here as oralit, IDR 1,000 to 3,000 a sachet in any apotek. Fluid is the treatment. Everything else is comfort.
- When to see a doctor: blood in the stool, real fever, no fluids staying down, or nothing improving after two days.
- When you can dive again: at least 24 hours after the last loose stool, and only once you are eating and drinking normally.
What Bali Belly Actually Is
Bali belly is a nickname for traveller's diarrhoea, which is a real and well-studied condition rather than a local curiosity. The CDC Yellow Book calls it the most predictable travel-related illness there is, with attack rates of 30 to 70 percent of travellers over a two week period depending on where and when you go. Between a third and two thirds. It is not bad luck and it is not a sign you did anything stupid.
The cause is almost always an organism you swallowed. Bacteria are the most common culprit, led by enterotoxigenic E. coli, followed by campylobacter, shigella and salmonella. Viruses account for a good share, mostly norovirus, which tends to involve more vomiting and less warning. Protozoa such as giardia are a smaller slice and behave differently, which we come back to below.
It is worth being precise about this, because there is a persistent story that Bali belly is your stomach adjusting to unfamiliar spices, or to a different local microbiome, and that you simply need a couple of days to acclimatise. That is not what is happening. Chilli does not give you a fever. What is happening is an infection, usually bacterial, and knowing that changes what you do about it: you rehydrate aggressively, you watch for a small number of warning signs, and in most cases you wait it out rather than reaching for antibiotics.
Symptoms, and the ones that matter
The usual picture is sudden. Watery stools, cramping, nausea, sometimes vomiting, sometimes a low fever, and a general flatness that makes the idea of a 7am pickup unthinkable. Most of that is unpleasant rather than dangerous.
The symptoms that change the situation are these: blood in the stool, a genuine fever rather than feeling warm, vomiting that stops you keeping any fluid down, signs of real dehydration such as very dark urine or not passing urine for many hours, severe or localised abdominal pain, and anything still going strong past the two day mark. Any one of those and you want a doctor rather than a pharmacy, and we will get to what that costs in Bali.
How You Really Catch It
You catch Bali belly by swallowing an organism that got into your food or water through kitchen hygiene you never see, not through the specific dish you were brave enough to order. That is the finding that surprises people, and it comes straight from the CDC rather than from us. The traditional advice, boil it, cook it, peel it or forget it, has been studied, and travellers who follow those rules still get sick at similar rates. The larger contributors are hygiene practices in kitchens you cannot see into and the underlying sanitation infrastructure, neither of which you control by declining a salad.
Which is not an argument for fatalism. It is an argument for spending your caution where it actually buys you something. In practice, on this island, that means a few specific things.
Busy places are safer than empty ones, and this is the single most useful rule we know. A warung with a queue of Indonesian office workers turns its food over in an hour. A tourist restaurant with four occupied tables is serving you something that has been sitting in a bain-marie since eleven. Turnover beats decor every time, and some of the safest food in Sanur is cooked in front of you on a cart.
Heat is the other reliable signal. Food that arrives steaming has been through a temperature that kills most of what matters. Food that arrives at room temperature has not, or has and then cooled down slowly, which is worse. Grilled satay handed to you off the coals is a better bet than a buffet that has been open for two hours, whatever the buffet costs.
Ice deserves a mention because the advice you have read is probably out of date. Commercial tube ice, the cylindrical stuff with a hole through the middle, is factory made from treated water and is used across the island in restaurants and cafes. It is fine. We drink it daily. The old blanket warning against all ice comes from a different era, and following it means drinking warm everything for two weeks for no benefit.
Tap water is genuinely not for drinking, and that part has not changed. Bottled or filtered water only, and use it for brushing your teeth if you want to be careful, though plenty of long-term residents do not bother. What catches more people than water is hands. You have been handling cash, scooter handlebars, menus and rental gear all day, and then you eat with your fingers. Hand sanitiser in your day bag is dull advice and it works better than avoiding salad.
How Long Bali Belly Lasts
Most Bali belly lasts three to seven days untreated when it is bacterial, which covers the majority of cases, and two to three days when it is viral. Giardia is the outlier and runs for weeks. So it depends on what you have, and the timing itself is the clue that tells you which one it is.
| Cause | Onset after exposure | Untreated duration | Typical feel |
|---|---|---|---|
| Bacterial (most cases) | 6 to 96 hours | 3 to 7 days | Sudden, cramping, can include fever |
| Viral (norovirus and similar) | 6 to 96 hours | 2 to 3 days | Sudden, vomiting more prominent |
| Protozoal (giardia) | 1 to 2 weeks | Weeks to months | Gradual, low grade, bloating, fewer stools per day |
Read that table backwards and it tells you something useful. If you got sick on day two of a two week trip, it is bacterial or viral and it will pass. If you are still unwell in week three, or you started feeling low grade and bloated rather than acutely ill, that is a different problem and it needs a stool test rather than patience. Giardia does not resolve because you are being brave about it.
Most people reading this have the first kind. Antibiotics shorten a bacterial case by roughly one to two days, which is worth knowing when you weigh them up, because it is less dramatic than people assume. A small number of people develop lingering gut symptoms after the infection has cleared, sometimes called post-infectious irritable bowel syndrome, and if that is you then it is a conversation with your own doctor at home rather than a Bali problem.
How to Avoid Bali Belly Without Living on Plain Rice
The precautions that actually reduce your risk are eating where the turnover is fast, eating food that arrives hot, and washing your hands before you touch it. Avoiding ice, salad and street food, which is what most people spend their caution on, does very little. We have watched a lot of guests try to outrun this and we have opinions about which precautions earn their keep.
Worth doing
- Eat where locals eat and where the queue is. Turnover is the whole game.
- Prefer food that arrives hot and cooked to order over anything held warm.
- Carry hand sanitiser and use it before you eat, every time, including at nice places.
- Bottled or filtered water, and enough of it. Most people in Bali are mildly dehydrated before anything goes wrong, which makes everything worse when it does.
- Bring oral rehydration salts and loperamide from home in your dive kit, along with the rest of your Bali scuba diving packing list. Both are available here cheaply, but at two in the morning you want them in your bag, not in a shop.
Not worth the misery
- Refusing all ice. Commercial tube ice is fine and the rule costs you two weeks of warm drinks.
- Avoiding all street food on principle. Some of it is the safest food on the island, because you watch it being cooked.
- Preventive antibiotics. Current guidance advises against them for almost all travellers, because side effects, the risk of picking up resistant bacteria and the disruption to your own gut outweigh the benefit for a self-limiting illness.
- Probiotics as insurance. Dosing yourself before you get ill is a different question from taking something once you are, and the evidence for preventing traveller's diarrhoea this way is thin. There is more on Lacto-B, which is what everybody here reaches for, further down.
One honest admission, since we are an operator and not a health authority: we get it too. Everyone who lives here does, occasionally, including staff who have been in Bali for fifteen years and eat the same food every day. It is not a purity test and it is not a sign you were careless.
What to Do in the First Six Hours
The treatment for most cases is boring and it is mostly fluid. Getting this right early is the difference between losing one day and losing three.
Start with oral rehydration salts, not water alone. In Indonesia the product is called oralit and it is in every pharmacy, which is an apotek, and every convenience store. Kimia Farma, Guardian, Century and Apotek K-24 all stock it, and a sachet costs somewhere between IDR 1,000 and 3,000. You dissolve one sachet in 200ml of clean water. It tastes of salty nothing and it works because plain water does not replace the sodium and potassium you are losing. This is the single highest value thing you can do, and it costs less than a bottle of water.
Skip the sugary drinks. The instinct to drink Coke or Pocari Sweat by the litre is understandable and it partly backfires, because heavily sweetened drinks can pull water into the gut and make the diarrhoea worse. Weak tea, clear broth, salted crackers and oralit are the boring, correct answer. Avoid dairy for a day or two.
Loperamide, with a condition attached. Imodium, sold here as Imodium or Diapet, will slow things down and is genuinely useful if you need to get through a car transfer or a flight. The standard regimen is 4mg to start, then 2mg after each loose stool, to a maximum of 16mg in 24 hours. The condition: do not take it on its own if you have a fever or blood in the stool, and do not take it with severe abdominal cramps. Those signs point at an invasive infection and slowing your gut down is the wrong move. See a doctor instead.
Do not start antibiotics on your own. For mild cases they are not indicated at all. For moderate or severe cases, current guidance for Southeast Asia points to azithromycin rather than ciprofloxacin, because campylobacter resistance to fluoroquinolones is widespread across this region. That is a prescription decision made by a doctor who has looked at you, not a decision made from a blog at three in the morning, and in Indonesia antibiotics require a local prescription anyway.
Eat when you feel like eating. The old advice to starve yourself has gone. Plain rice, bananas, crackers, soup, and then normal food as your appetite returns. Bubur ayam, the local chicken rice porridge, is what Indonesians eat when they are unwell, it is available everywhere in the morning for around IDR 20,000, and it is genuinely good for this.
Does Lacto-B Work for Bali Belly?
Not as a cure, no, but it is cheap and harmless and it is what people here reach for first. Ask any Balinese parent what to do about a bad stomach and they will tell you Lacto-B. It is a probiotic powder made by Novell, it comes in 1 gram sachets, it costs somewhere between IDR 7,000 and 15,000 in any apotek, and although the box is aimed at children aged one to twelve, adults here take it three times a day without a second thought. Our own staff swear by it and there is usually a strip of it in somebody's bag at the shop.
Both halves of the honest answer, then. It is cheap, it is safe, it contains live Lactobacillus acidophilus, Bifidobacterium longum and Streptococcus thermophilus along with a few B vitamins, and if it makes you feel better then take it. The caveat is that the best current evidence does not support it as a cure. The 2020 Cochrane review of probiotics for acute infectious diarrhoea, looking only at the trials at low risk of bias, found they probably make little or no difference to whether the diarrhoea lasts beyond 48 hours. Probiotics do have better evidence behind them for the separate problem of antibiotic-associated diarrhoea, but the doses that worked in those trials were 5 billion CFU a day and upwards, and a Lacto-B sachet carries around 10 million.
So take it if you want to, because it will not hurt you and plenty of people here are genuinely convinced by it. Just do not let it stand in for the oralit, because rehydration is the part doing the actual work. One exception worth naming: if you are immunocompromised, ask a doctor before taking any live-bacteria product.
When You Need a Doctor, and What It Costs in Bali
Go and see someone if you have blood in the stool, a real fever, vomiting that prevents you keeping fluids down, signs of significant dehydration, severe abdominal pain, or symptoms that are still going after about two days. Also go if it is a young child, because children dehydrate far faster than adults do.
Bali is genuinely well set up for this and the care is good. What surprises people is the billing. Indonesia's national health system is not available to short-stay visitors, so everything is private and paid up front, then claimed back on your travel insurance. Bring the receipts.
| Option | Typical cost | When it makes sense |
|---|---|---|
| Pharmacy (apotek): oralit, loperamide, paracetamol | IDR 5,000 to 50,000 | The overwhelming majority of cases |
| Private clinic GP consultation | IDR 300,000 to 600,000 | Symptoms past two days, or you want a prescription |
| Clinic visit including basic treatment | IDR 500,000 to 1,000,000 | Moderate illness, you can still travel to them |
| Mobile doctor and IV drip at your hotel | IDR 1,800,000 to 2,550,000 | You genuinely cannot keep fluids down |
| Private hospital episode with tests | IDR 2,500,000 to 5,000,000 and up | Fever with blood, or something that is not this |
For serious illness the international-standard options are the ones we point guests at across the island: BIMC in Kuta and Nusa Dua, and Siloam in Denpasar, all with English-speaking staff and used to treating visitors.
The IV drip question
Bali has a thriving industry of mobile doctors who will come to your villa and put you on a drip, and they advertise heavily to exactly the person reading this at 4am. So, plainly: if you cannot keep oral fluids down, or you are genuinely dehydrated, an IV is the right treatment and IDR 2,000,000 is money well spent. It works fast and you will feel human within the hour.
If you can drink, it is almost always unnecessary. Oralit does the same job through a slower route for two thousand rupiah. We have had guests spend two million on a drip for a case that a pharmacy sachet and a quiet afternoon would have fixed, and then feel obliged to dive the next day because they had paid for the recovery. Nobody in that chain was acting in their own interest. Ask yourself one question before you book the drip: can I keep water down? If yes, try oralit properly for a few hours first.
Can You Dive With Bali Belly?
No, and this is the one place in this article where we are not going to soften it. Divers Alert Network puts it in one line: do not dive if you have diarrhoea. The reasons stack up and each one is independently sufficient.
Dehydration and decompression sickness. Being dehydrated is a recognised contributor to DCS, and a night of fluid loss is a serious dehydration, layered on top of everything Bali already does to you. Thirty degrees on the boat deck, sun coming off the water, a long transfer and the diuretic effect of immersion itself all stack before you consider the stomach bug. We go through the whole picture in our guides to how to avoid decompression sickness and the hyperbaric chamber in Bali, and dehydration turns up in both.
Vomiting underwater. It is survivable. A modern regulator has a one-way exhaust and you can be sick through it and keep breathing, and every instructor has a story. It is also a genuine route to aspiration and to panic at depth, and panic is what actually hurts people. This is not a risk worth accepting for one dive on a holiday.
Fever. A raised temperature lifts your metabolic rate, which increases your air consumption and shortens the dive, and it clouds judgement at exactly the moment you need it. Nobody makes good decisions at 25 metres with a fever.
The obvious one. There is no discreet solution to diarrhoea in a wetsuit on a boat with one toilet and eleven other people. We have all seen it handled badly and nobody wants to be the story.
You are infectious. Norovirus in particular moves through a dive boat, and on a liveaboard it can take out half the guests. This is the part people forget because they are focused on their own week.
What about loperamide and seasickness tablets?
Taking loperamide to get through a dive day is the question we get asked most, usually phrased as though there must be a trick. There is no specific interaction between loperamide and diving, and the DDRC guidance on gastroenteritis and fitness to dive says as much. But it treats the symptom and not the dehydration, it does not always work, and it does nothing about the fever or the fatigue. Using it to mask your way onto a boat is a bad plan wearing a sensible hat.
Seasickness tablets are a separate trap. Many of them are sedating, and a drowsy diver is a hazard to themselves and to their buddy. If you need something for the crossing, take the non-drowsy formulation and take it the night before rather than on the boat.
When Can You Dive Again After Bali Belly?
The benchmark DAN gives is at least 24 hours after your last loose stool, and that is a floor rather than a target. Two conditions have to be met on top of the clock.
First, you need to be symptom-free. Not improving, not manageable, actually finished. Second, you need to be properly rehydrated, and the practical test is your urine: pale and plentiful, not dark and occasional. If you have not needed the bathroom in six hours you are not ready, however good you feel.
Add a third for anything beyond a mild case. A bad two or three days costs you strength and sleep, and a dive is physical work. Carrying a tank down a Tulamben beach of black cobbles is not a gentle activity, and neither is the current at Gili Mimpang and Tepekong off Candidasa. If you feel wobbly climbing a flight of stairs, restart on something forgiving. The house reef at our dive centre in Sanur is flat, shallow and five minutes from a bathroom, which is exactly what you want on day one back. Save the long day out to Menjangan Island, which is twelve to fourteen hours door to door, until you are properly back on your feet.
| Situation | Earliest sensible return |
|---|---|
| Mild, one bad night, no fever | 24 hours after the last episode, if fully rehydrated |
| Moderate, two to three days, some fever | 24 to 48 hours symptom-free, and start with an easy site |
| Severe, or you needed IV fluids | Several days, and get the treating doctor's view |
| Blood in the stool, or antibiotics prescribed | Ask the doctor who prescribed them, not us |
| Still unwell after two weeks | Stop diving, get a stool test, think giardia |
A note for anyone mid-course. If you are partway through a PADI Open Water Diver course in Bali and this happens, it is not a disaster. Course dives do not have to be consecutive, we hold your paperwork, and we can usually pick up where you left off a day or two later. The same goes for the PADI Advanced Open Water course in Bali. What we cannot do is sign off skills you performed badly because you were ill, so pushing through tends to cost you more time than resting does.
What We Do When a Guest Goes Down With It
We move your dive day and we do not charge you a no-show fee. That is the policy, stated plainly so you can hold us to it.
Message us as early as you can, even if it is 5am, and we will move your dive day rather than charge you for a no-show. We would far rather reschedule than have a sick diver on the boat, and that is self-interest as much as kindness: an unwell guest is a safety problem, a risk to the day for everyone else, and a potential norovirus vector in a confined space. Moving you is the cheap outcome for us.
What we can usually do is shuffle. Swap your Nusa Penida day for later in the week and bring forward a rest day. Move you off a long transfer to Tulamben or Amed and onto something closer like Padang Bai, which is 90 minutes away instead of two and a half hours. Drop you from two dives to one. Put you on a snorkelling trip in Bali or snorkelling at Nusa Penida instead of a dive, which asks far less of you physically and gets you out of the hotel room. If a non-diving partner has been sitting out your dive days anyway, a try dive in Bali slots neatly into the day you were about to lose.
What we will not do is take you diving because you insist. We have had that conversation on the pier more than once and it is awkward for about four minutes and correct for the rest of the trip. If you want to argue the point, argue it with us over a bottle of water and we will find you another day. Building a buffer day into the plan in the first place is the real fix, which is one reason our Bali dive trip itinerary never books dives on every single day.
One booking note worth knowing. Do not schedule your last dive for the day before your flight. Between the surface interval you need before flying and the chance of losing a day to this, a trip with no slack in it is a trip where something gets cut. Leave a spare day at the end and it is the cheapest insurance in the whole plan. Rates for everything are on the Bali diving price list, and you can always talk to our Sanur team before you lock the dates in.
Bali Belly, Kids and Liveaboards
Children and liveaboards are the two situations where Bali belly stops being merely miserable. Small children dehydrate fast enough that a day of waiting it out is a real risk, and on a liveaboard there is no pharmacy, no doctor and no easy way ashore. Both deserve their own treatment because the stakes are different.
Children
Children dehydrate much faster than adults, and with infants and toddlers the margin is genuinely small. Oral rehydration solution is the main treatment, started early rather than once things look bad, and given in small frequent amounts rather than a glass at a time, because a large volume on an upset stomach comes straight back. Watch for dry mouth, no tears when crying, sunken eyes, unusual drowsiness and a long gap without a wet nappy. Any of those and see a doctor the same day rather than waiting it out.
The good news is that Sanur and the southern tourist areas are well supplied with clinics used to seeing tourist children, and treatment is quick. If you are travelling with a family and building dive days around them, our guide to diving with kids in Bali covers how we structure those trips, and slack in the schedule matters even more with children in the group.
Liveaboards and remote trips
A stomach bug on a boat in Komodo or the Banda Sea is a different order of problem, because you cannot walk to a pharmacy and the nearest hospital may be a day away. If you are booked on an Indonesia liveaboard, bring a personal kit: oral rehydration salts, loperamide, and a doctor-prescribed standby course of azithromycin if your travel clinic agrees it is appropriate for you. Get the prescription and the written instructions before you leave home, because Indonesian pharmacies cannot dispense against a foreign prescription.
Also take the shared-space part seriously. Wash hands before every meal on board, and tell the crew immediately if you are unwell rather than quietly hoping it passes. A single unreported norovirus case has ended more than one liveaboard week for everybody on it.
The summary we would give you across the counter: most Bali belly is bacterial, most of it passes in a few days, oralit from any pharmacy is worth more than anything else you can buy, antibiotics are a doctor's call rather than yours, and no dive is worth doing dehydrated. Move the day. The reef will still be there on Thursday, and you will enjoy it considerably more. If you want to plan a trip with enough slack in it that a bad night does not wreck the week, have a look at scuba diving in Bali and talk to us about the dates.
This article is general information from a dive operator, not medical advice, and it does not replace a doctor who can actually look at you. For the wider medical side of a Bali trip, including what is and is not worth vaccinating against, see our health and vaccinations guide for divers in Bali, and the CDC destination page for Indonesia is the authoritative source for pre-travel planning.