When you have stomach flu, the best approach is to focus on fluids first and then eat whatever bland, easy-to-digest foods you can tolerate as soon as your appetite returns. You don’t need to follow a strict diet or force yourself to fast. The priority is replacing the water and electrolytes you’re losing through vomiting and diarrhea, then gradually getting calories back in.
Fluids Come First
Dehydration is the real danger with stomach flu, not the virus itself. Every bout of vomiting or diarrhea pulls water and essential minerals out of your body. If you can’t keep anything else down, sip small amounts of fluid constantly rather than drinking large quantities at once, which can trigger more vomiting.
The gold standard for rehydration is an oral rehydration solution, which contains a precise balance of sodium and glucose in a 1:1 ratio. That ratio matters because sodium and glucose travel together across your intestinal wall, pulling water along with them. You can find oral rehydration solutions at any pharmacy (common brands include Pedialyte and DripDrop), or you can make a basic version at home with water, salt, and sugar.
Sports drinks are a common go-to, but they’re not ideal. A typical sports drink contains about three times less sodium and nearly twice as much sugar as an oral rehydration solution. That extra sugar without enough sodium can actually work against you: high sugar concentrations draw water into your intestines instead of helping your body absorb it, which can make diarrhea worse. If a sports drink is all you have, dilute it with water. Other good options include clear broth, coconut water, and weak tea. Avoid fruit juice, soda, and energy drinks for the same sugar-related reason.
What to Eat as Appetite Returns
You’ve probably heard of the BRAT diet: bananas, rice, applesauce, and toast. It’s fine for a day or two, but Harvard Health Publishing notes there’s no actual research showing it works better than simply eating a broader range of bland foods. And because it’s nutritionally limited, sticking with only those four foods for longer than a couple of days can slow your recovery by depriving your body of protein and fat it needs to heal.
A better approach is to eat from a wider list of gentle, low-fat, low-fiber foods. Good options include:
- Starches: white rice, plain crackers, boiled potatoes (without skin), oatmeal, unsweetened dry cereal, plain pasta
- Soups: chicken broth, vegetable broth, simple noodle soup
- Fruits: bananas, applesauce, canned peaches
- Proteins: skinless chicken or turkey, plain scrambled eggs, baked fish
- Vegetables (cooked): carrots, butternut squash, sweet potatoes without skin
The NIDDK, part of the National Institutes of Health, is direct on this point: research shows that following a restricted diet does not help treat viral gastroenteritis. Most experts recommend returning to your normal diet as soon as your appetite allows, even if you still have some diarrhea. For children, the same guidance applies. Give them what they normally eat once they’re ready.
Foods and Drinks to Avoid
While you don’t need to be overly restrictive, certain foods are genuinely harder on an inflamed gut. Fatty and greasy foods slow gastric emptying, meaning food sits in your stomach longer and increases the chance of nausea. Large meals have the same effect. Eating smaller portions more frequently is easier on your system than three full meals.
High-fiber foods like raw vegetables, whole grains, beans, nuts, and seeds are harder to break down and can increase bloating and cramping. Spicy foods irritate an already inflamed digestive tract. Caffeine and alcohol are both dehydrating, which is the opposite of what you need right now.
Sugary foods and drinks deserve special attention. When too much sugar enters your intestines without being absorbed, it pulls water in after it, a process called osmotic diarrhea. This is why full-strength juice, regular soda, and candy can make your diarrhea noticeably worse. Even naturally sweet foods like dried fruit can have this effect in larger amounts.
Skip Dairy for a Few Weeks
Stomach flu viruses, particularly rotavirus, can damage the lining of your small intestine where lactase, the enzyme that digests milk sugar, is produced. This means you may develop temporary lactose intolerance even if you normally handle dairy just fine. Drinking milk or eating ice cream during or shortly after stomach flu can cause bloating, cramps, and more diarrhea.
This temporary intolerance typically resolves within three to four weeks as the intestinal lining repairs itself. During that window, you’re better off avoiding milk, soft cheese, and ice cream. Yogurt is often tolerated because the bacteria in it help pre-digest some of the lactose, but listen to your body. Hard cheeses like cheddar contain very little lactose and are usually safe.
Ginger for Nausea
If nausea is your main barrier to eating, ginger is one of the most studied natural remedies. Clinical trials have used doses ranging from 250 mg to 1 g per day, split into three or four smaller doses, with no additional benefit seen at higher amounts. In practical terms, that’s a few cups of real ginger tea (made from sliced fresh ginger, not ginger-flavored tea), ginger chews, or ginger capsules from a pharmacy. Ginger ale is an option only if it contains real ginger, which most commercial brands don’t.
Probiotics May Shorten Recovery
There’s evidence that probiotics can trim the duration of diarrhea by roughly a day. A meta-analysis covering over 1,700 children with acute gastroenteritis found that those given probiotics had diarrhea lasting about 23 hours less than those who didn’t, and the chance of diarrhea continuing past 48 hours dropped by 30%. The evidence is stronger in children than adults, and the certainty of the data is considered low, but given that probiotics carry minimal risk, they’re a reasonable addition. Look for products containing Lactobacillus or Bifidobacterium strains, which have the most research behind them. Yogurt with live active cultures counts if your stomach can handle it.
Signs of Dehydration to Watch For
The biggest risk with stomach flu isn’t the infection itself. It’s losing more fluid than you can replace. In adults, warning signs include urinating much less frequently than normal, dark yellow urine, dry mouth and lips, dizziness when standing up, and a rapid heartbeat at rest. Skin that stays “tented” when you pinch it (instead of snapping back flat) is another reliable indicator.
In children, look for no tears when crying, sunken eyes, dry diapers for several hours, and poor responsiveness. A simple check: press on their fingernail until it turns white, then release. If the pink color takes more than two seconds to return, that suggests significant dehydration. These signs warrant prompt medical attention, especially in infants and older adults who can deteriorate quickly.