What to Eat With a Stomach Bug: A Practical Food Guide

Published on 22 October, 2026

Two pieces of standard advice about stomach bugs have quietly been retired. The bananas-rice-applesauce-toast (BRAT) diet is no longer recommended, and probiotics turned out not to work. What replaced them is less interesting and considerably more effective: rehydration salts, and going back to normal food sooner than feels natural.

Vomiting and diarrhea are the subject below. Colds, flu and fever follow different rules, and our guide to what to eat when you are sick covers those.

Rehydration: The Main Treatment for a Stomach Bug

Almost everything that makes a stomach bug dangerous is fluid and salt loss rather than the infection itself. In a healthy adult the illness resolves on its own in one to three days. The job in the meantime is replacing what is being lost, and plain water does that incompletely because it replaces the fluid without the sodium, potassium and glucose that went with it.

Oral rehydration solution exists for exactly this. The glucose and sodium are matched so that the sodium-glucose cotransporter in the gut wall pulls both across together, dragging water with them, and this pathway keeps working even when the gut is inflamed and secreting fluid. It is the reason oral rehydration works at all rather than simply passing through.

Buy commercial oral rehydration sachets if you can. They are inexpensive, shelf-stable, and mixed to the right proportions.
The World Health Organization home recipe is six level teaspoons of sugar and half a level teaspoon of salt dissolved in one liter of clean water. Measure it properly, because too much sugar makes diarrhea worse.
Sip small amounts often. A few mouthfuls every five or ten minutes stays down when a full glass does not.
After vomiting, wait around thirty minutes, then restart with very small sips.
Aim to replace roughly a cup of fluid after each loose stool, on top of what you would normally drink.

Why Sports Drinks Are Not Ideal for a Stomach Bug

They were formulated for sweat loss during exercise, which is a different problem. Sweat is relatively dilute; diarrheal stool is not. A typical sports drink carries far more sugar and far less sodium than rehydration solution needs.

The excess sugar matters, because unabsorbed sugar draws water into the bowel osmotically and can lengthen the diarrhea you are trying to stop. The same objection applies to undiluted fruit juice and regular soda. If a sports drink is genuinely all you have, dilute it with an equal volume of water and add a pinch of salt.

Is the BRAT Diet Still Recommended?

Bananas, rice, applesauce and toast were recommended for decades on the reasoning that bland, low-fiber, binding foods rest the gut. The advice was dropped because it is nutritionally thin, provides very little protein or fat, and keeping someone on it delays recovery rather than speeding it.

The evidence moved toward early refeeding. Returning to a reasonably normal diet as soon as it can be tolerated is associated with shorter illness and better nutritional outcomes than prolonged restriction. None of those four foods is harmful; they are simply a starting point rather than a diet.

What to Eat at Each Stage of a Stomach Bug

Stage	What to take	Notes
Actively vomiting	Rehydration solution only, in sips	Food will not stay down and is not needed yet
Vomiting settled, 4 to 6 hours	Rehydration solution plus dry toast, plain rice, crackers, banana	Small amounts, see what holds
Keeping food down	Add potato, oatmeal, soup, cooked vegetables, eggs	Protein and energy matter more than blandness now
Day two onward	Return to normal food	Early refeeding shortens illness rather than prolonging it
Lingering loose stools	Normal food, consider skipping milk briefly	Transient lactose intolerance is common after gastroenteritis

Fatty and heavily spiced food, alcohol and caffeine are worth avoiding for a day or two, not because they are dangerous but because they tend to be poorly tolerated by an irritated gut.

Do Probiotics Help a Stomach Bug?

A 2018 trial in the New England Journal of Medicine gave 943 preschool children with acute gastroenteritis either a five-day course of Lactobacillus rhamnosus GG or placebo. Median diarrhea duration was 49.7 hours with the probiotic and 50.9 hours with placebo. There was no difference in vomiting, in day-care absence, or in household transmission.

A Cochrane review published in 2020 then pooled the large, low-bias trials and reached the same place: probiotics probably make little or no difference to whether diarrhea lasts 48 hours or longer, and whether they shorten its duration at all is uncertain. Earlier enthusiasm came from many small trials with publication bias visible in the funnel plots.

Probiotics are not harmful here, and no serious adverse events were attributed to them. They are simply not the treatment, and buying them instead of rehydration salts is a poor trade. Our guide to prebiotics and probiotics covers where they do have better support.

Anti-Diarrheal Medication

Loperamide slows gut transit and can be reasonable for an otherwise healthy adult with watery diarrhea and no fever, where the practical problem is needing to travel or work.

It should be avoided with a high fever, with blood in the stool, or in suspected bacterial dysentery, where slowing clearance of the organism can make matters worse. It should not be given to young children. Diarrhea is partly a clearance mechanism, and suppressing it is a convenience decision rather than a treatment.

How to Stop a Stomach Bug From Spreading

Norovirus, the usual cause in adults, is unusually contagious and unusually hardy.

Alcohol hand sanitizer works poorly against norovirus, because the virus is non-enveloped and alcohol does not disrupt it well. Soap and water with physical scrubbing is the method that works.
People stay infectious after symptoms stop, commonly for 48 hours and sometimes considerably longer. The 48-hour rule before returning to work, school or food handling exists for this reason.

Wash hands properly after using the bathroom and before handling food, do not prepare food for others while ill or for two days afterward, and clean contaminated surfaces with a bleach-based product rather than a general-purpose spray.

Stomach Bug Symptoms That Need a Doctor

Signs of significant dehydration, including not passing urine for eight hours or more, dizziness on standing, sunken eyes or a dry mouth with no saliva.
Unable to keep any fluid down for 24 hours, which is the point at which oral rehydration has failed.
Blood in the stool or in vomit, or black tarry stools.
Severe or localized abdominal pain, particularly if it concentrates in one area rather than cramping diffusely.
Diarrhea lasting longer than a week, or a fever above 102 degrees Fahrenheit.
Infants, older adults, pregnant women and anyone immunocompromised, where the threshold for getting advice should be considerably lower.

YO1 is not a medical center and does not have physicians on staff; its practitioners do not diagnose or prescribe.

Lingering Symptoms After a Stomach Bug

Appetite and normal bowel habit usually return within a few days. If loose stools persist for a couple of weeks after everything else has resolved, transient lactose intolerance is the common explanation, caused by temporary damage to the enzyme-producing cells at the tips of the intestinal villi. It recovers, and briefly reducing milk while keeping yogurt and hard cheese is usually enough to manage it.

Genuinely persistent symptoms deserve investigation rather than dietary tinkering. Post-infectious irritable bowel syndrome is a recognized outcome after gastroenteritis, and it is a diagnosis to reach with help rather than guess at.

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FAQs

Q: What should I eat with a stomach bug?

A: Nothing at all while actively vomiting; oral rehydration solution is the priority. Once vomiting settles, start with small amounts of toast, plain rice, crackers or banana, then return to normal food within a day or two. Early refeeding shortens the illness rather than prolonging it.

Q: Is the BRAT diet still recommended?

A: No. Bananas, rice, applesauce and toast are nutritionally thin, and staying on them delays recovery. They are fine as a first food after vomiting stops, but returning to a reasonably normal diet as soon as it is tolerated produces better outcomes.

Q: Do probiotics help a stomach bug?

A: The evidence says no. A 2018 New England Journal of Medicine trial in 943 children found a five-day course of Lactobacillus rhamnosus GG no better than placebo, and a 2020 Cochrane review of the large low-bias trials found probiotics probably make little or no difference to diarrhea lasting 48 hours or more.

Q: Can I just drink water?

A: Water alone replaces fluid without the sodium, potassium and glucose lost in diarrhea. Oral rehydration solution is matched so the gut absorbs sodium and glucose together, pulling water across with them, and that pathway keeps working even when the gut is inflamed.

Q: Are sports drinks good for diarrhea?

A: Not especially, because they were designed for sweat loss, so they carry too much sugar and too little sodium for diarrheal losses, and the excess sugar can draw water into the bowel and worsen the diarrhea. If it is all you have, dilute it half-and-half with water and add a pinch of salt.

Q: How do I make oral rehydration solution at home?

A: The World Health Organization recipe is six level teaspoons of sugar and half a level teaspoon of salt dissolved in one liter of clean water. Measure accurately, because too much sugar makes diarrhea worse. Commercial sachets are cheap and more reliable.

Q: Should I take anti-diarrheal medication?

A: It can be reasonable for a healthy adult with watery diarrhea and no fever. Avoid it with a high fever, blood in the stool or suspected bacterial dysentery, where slowing clearance of the organism can make things worse, and do not give it to young children.

Q: Should I avoid dairy after a stomach bug?

A: Briefly, if loose stools persist. Gastroenteritis temporarily damages the cells producing lactase, so transient lactose intolerance is common and usually resolves within a couple of weeks. Yogurt and hard cheese are generally tolerated even when milk is not.

Q: How long am I contagious?

A: Commonly for at least 48 hours after symptoms stop, and sometimes longer with norovirus. That is why the standard advice is to stay away from work, school and food preparation for two full days after the last episode.

Q: Does hand sanitizer kill norovirus?

A: It works poorly, because norovirus is non-enveloped and alcohol does not disrupt it well. Washing with soap and water, with real physical scrubbing, is the method that works, and contaminated surfaces need a bleach-based cleaner rather than a general-purpose spray.

Sources

Schnadower D, et al. Lactobacillus rhamnosus GG versus Placebo for Acute Gastroenteritis in Children. N Engl J Med. 2018. PMID: 30462938
Collinson S, et al. Probiotics for treating acute infectious diarrhoea. Cochrane Database Syst Rev. 2020. PMID: 33295643

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