Most cases of vomiting and diarrhea in adults are caused by a stomach virus or food poisoning and will resolve on their own within one to three days. The priority while you wait is preventing dehydration, calming your stomach enough to keep fluids down, and knowing when symptoms cross into something more serious. Here’s what actually works.
Figure Out What You’re Dealing With
The two most common culprits are viral gastroenteritis (stomach flu) and food poisoning, and the timeline tells you a lot. Food poisoning hits fast, typically two to six hours after eating contaminated food, and tends to run its course quickly. A stomach virus has a longer incubation period of 24 to 48 hours before symptoms start, and it usually lasts one to three days.
The distinction matters because food poisoning is often over before you’d need to intervene much beyond hydration, while a stomach virus can drag on long enough to cause real fluid loss. Either way, the management strategy is similar: replace what you’re losing, eat when you can, and let your gut recover.
How to Keep Fluids Down When You’re Vomiting
The biggest mistake people make is drinking too much at once. A full glass of water on an actively upset stomach will come right back up. Instead, start with one teaspoon (5 ml) to one tablespoon (15 ml) of liquid at a time. If that stays down, slowly increase the amount over the next hour or two. If vomiting starts again, take a 30 to 60 minute break and restart the process with small sips.
What you drink matters as much as how much. Plain water replaces volume but not the sodium and potassium you’re losing through vomiting and diarrhea. Oral rehydration solutions are the gold standard because they contain the right balance of salt, sugar, and water to help your body absorb fluid efficiently. You can buy premixed versions at any pharmacy. The CDC recommends adults with vomiting or diarrhea aim for about 3 liters of oral rehydration solution per day, though you’ll build up to that gradually. Broth, diluted juice, and sports drinks are reasonable alternatives, though sports drinks contain more sugar and less sodium than ideal.
Avoid coffee, alcohol, and full-strength fruit juice. All three can irritate your stomach or pull water into your intestines, making diarrhea worse.
Over-the-Counter Options That Help
Loperamide (the active ingredient in Imodium) slows gut contractions and can reduce the frequency of diarrhea. It’s meant for short-term use only, no more than two days unless your doctor says otherwise. Do not take it if you have a fever, blood in your stool, or severe abdominal pain, as these can signal a bacterial infection where slowing your gut down is the wrong move. Overuse of loperamide can also cause serious heart rhythm problems, so stick to the package directions.
Bismuth subsalicylate (the active ingredient in Pepto-Bismol) can help with both nausea and diarrhea. It coats the stomach lining and has mild antibacterial properties. It will turn your tongue and stool black temporarily, which is harmless. Avoid it if you take blood thinners or are allergic to aspirin, since it’s chemically related.
For nausea specifically, anti-nausea medications containing dimenhydrinate (Gravol, Dramamine) can help you keep fluids and food down. These cause drowsiness, which can actually be a benefit when you’re sick and need rest.
What to Eat During Recovery
You may have heard of the BRAT diet: bananas, rice, applesauce, and toast. It’s a useful starting point, but doctors no longer recommend following it strictly for more than a day because it lacks protein, calcium, vitamin B12, and fiber. Think of BRAT as a reminder of the types of foods that are gentle on your stomach rather than a complete meal plan.
The current advice is to eat as tolerated. Once you can keep fluids down, try small amounts of bland, soft food: plain crackers, boiled potatoes, plain pasta, scrambled eggs, or chicken breast. If it stays down and doesn’t make you feel worse, eat more. Your body needs calories and nutrients to recover, so restricting yourself to four foods for days on end actually slows healing. Avoid greasy, spicy, or dairy-heavy foods until your gut feels more settled, as these are harder to digest and more likely to trigger another round of symptoms.
Probiotics for Faster Recovery
Certain probiotic strains can shorten the duration of diarrhea, particularly if your symptoms were triggered by antibiotics. A Cochrane review found that Lactobacillus rhamnosus and Saccharomyces boulardii at doses of 5 to 40 billion colony-forming units per day were effective at preventing antibiotic-associated diarrhea. S. boulardii is a yeast-based probiotic available over the counter (often sold as Florastor) and has the most evidence behind it for gut-related illness. It won’t stop vomiting, but it may help your intestinal lining recover faster and reduce the number of days you’re dealing with loose stools.
How to Tell If You’re Getting Dehydrated
Dehydration is the real danger with prolonged vomiting and diarrhea. Your body can lose fluid faster than you can replace it, especially if you can’t keep anything down. Watch for these signs: dark yellow or orange urine, urinating much less frequently than normal, dry mouth, excessive thirst, dizziness when you stand up, and general weakness. If your urine is pale yellow, you’re doing a reasonable job staying hydrated. If it’s consistently dark or you haven’t urinated in many hours, you need to push fluids more aggressively or seek medical help for intravenous hydration.
When Symptoms Signal Something Serious
Most stomach bugs don’t need medical attention, but certain warning signs change that calculus. Get to urgent care or an emergency room if you notice any of the following:
- Blood in your vomit or stool, or vomit that looks like coffee grounds
- Green vomit, which can indicate a bowel obstruction
- High fever with a stiff neck
- Severe abdominal pain or cramping that doesn’t come and go but stays constant
- Signs of significant dehydration like dizziness, dark urine, weakness, or very dry mouth
- Confusion or blurred vision
- Chest pain
You should also see a doctor if vomiting lasts more than two days, or if you’ve been having recurring bouts of nausea and vomiting for longer than a month. Persistent symptoms can point to conditions beyond a simple virus, including gallbladder problems, inflammatory bowel disease, or food intolerances that need proper evaluation.
A Practical Timeline for Getting Through It
In the first few hours, focus entirely on small sips of fluid. Don’t force food. Rest as much as possible, since sleep gives your immune system its best shot at clearing the infection quickly. If you’re vomiting frequently, set a timer for every five to ten minutes and take a single sip of oral rehydration solution or broth each time.
By 12 to 24 hours, vomiting usually slows down even if diarrhea continues. This is when you can start introducing bland foods in small amounts. Keep pushing fluids, aiming to drink a little with every meal and between meals. Consider adding a probiotic at this stage.
By 48 to 72 hours, most people are past the worst of it. Gradually return to your normal diet, saving rich or heavy foods for last. Your gut lining takes a few days to fully repair, so mild bloating or loose stools for up to a week after the acute phase isn’t unusual. If diarrhea hasn’t improved at all after two days of loperamide use, or if new symptoms develop like fever, stop self-treating and get evaluated.