Short answer first: for most people, food poisoning runs its course in 12 to 72 hours. The exact number depends entirely on what caused it — a virus, a bacterium, or a toxin — and each of those moves through your body on a different clock. Knowing the difference helps you plan, and more importantly, it helps you spot the one or two scenarios where “wait it out” is the wrong move.
This guide breaks down realistic timelines by cause, what to eat (and what to skip) while your stomach is in revolt, how long you’re contagious, and the specific red flags that mean you should see a doctor rather than ride it out on the couch.
How long does food poisoning last, in plain terms
Most food poisoning is a short, miserable, self-limiting event. Nausea, vomiting, diarrhea, and sometimes cramping and a low-grade fever show up fast — often within a few hours of eating — and then fade. In the large majority of cases, you’re feeling close to yourself again within a day or two.
Key takeaway: If you’re otherwise healthy, the safest default is to hydrate, eat bland foods, and rest. Most food poisoning doesn’t need medicine and doesn’t last more than two to three days.
That said, “most” is doing a lot of work in that sentence. Some causes — certain bacteria and some shellfish toxins — can linger for a week or more, and a few can become serious fast. The table below is where the “it depends” actually lives.
Why the duration depends on the cause
The reason the same “bad sushi” can make one person sick for 8 hours and another for a week is that the culprit sets its own timeline. Here’s a practical breakdown:
| Cause | Type | Typical onset | Typical duration |
|---|---|---|---|
| Norovirus | Viral | 12–48 hours | 1–3 days |
| Rotavirus | Viral | 1–3 days | 3–8 days (mostly kids) |
| Staphylococcus aureus (toxin) | Bacterial toxin | 1–6 hours | 6–24 hours, rarely 48 |
| Salmonella | Bacteria | 6–72 hours | 4–7 days |
| E. coli (STEC) | Bacteria | 3–4 days | 5–10 days |
| Campylobacter | Bacteria | 2–5 days | 5–10 days, can be longer |
| Clostridium botulinum | Toxin | 12–36 hours | days to weeks (needs care) |
| Cyclospora / parasites | Parasite | up to 1 week | weeks if untreated |
Two things jump out. First, the “toxin” and “bacteria” rows can feel identical to you — both are “food poisoning” — but the pre-formed toxin ones (like Staph from a mayonnaise-laden sandwich or Bacillus from reheated rice) often start and end faster. Second, parasites are the slow burn: if your symptoms drag past a week, that’s the category to ask a doctor about.
The pattern to remember: fast onset (within hours) usually points to a pre-formed toxin, which tends to resolve quickly. Slow onset (days) usually points to a living organism — bacteria or parasite — that can take longer and, in some cases, needs treatment.
What to eat and drink while your stomach is upset
The goal for the first day or two isn’t nutrition — it’s not aggravating your stomach and keeping your fluid up. Guidance from clinicians generally converges on the same simple playbook.
Drink first, eat second. The biggest risk in food poisoning, especially in older adults and young children, is dehydration. Small, frequent sips beat big gulps. Good options:
- Oral rehydration solutions (the pharmacy kind) — genuinely the most effective option for replacing lost salts
- Plain water
- Diluted clear juice
- Clear broth or bouillon
- Ice chips, if liquids sit poorly
Then reintroduce bland, low-fat, low-fiber foods. The classic BRAT idea (bananas, rice, applesauce, toast) is a fine starting point. You can also add:
- Plain crackers or saltines
- Plain white rice
- Bananas
- Boiled or baked potato, no butter
- Baked plain chicken or turkey, not fried
- Plain noodles
The fat and fiber you’d normally eat will slow digestion and add cramping when your gut is inflamed, so keep those out for a while.
What to avoid for the first 24 to 48 hours
These make a rough stomach noticeably worse, so skip them until you’ve had a couple of solid, symptom-free meals in a row:
- Dairy, especially if the diarrhea is bad
- Fatty, fried, or greasy foods
- High-fiber vegetables and raw salads
- Caffeine — it’s a mild diuretic and a gut irritant
- Alcohol
- Very spicy food
- High-sugar drinks and sodas, which can pull water into the gut and worsen diarrhea
You don’t have to live on crackers forever. As your appetite returns and your stools normalize, gradually re-add normal foods — but one at a time, so you know which one bothers you if anything does.
How long are you contagious, and when can you go back to work?
For the viral culprits (norovirus in particular), you’re most contagious during the symptomatic phase and can keep shedding the virus for a couple of weeks after you feel better. In practical terms:
- If you work with food, kids, or vulnerable adults, most guidance keeps you home until at least 48 hours after your last symptom.
- For everyday family life, you’re lowest-risk once you’re symptom-free, but wash your hands like you mean it — norovirus is extremely contagious and regular hand soap is one of the few reliable defenses (it’s not very sensitive to alcohol gel).
- If symptoms come and go over days, that’s more consistent with a bacterial or parasitic cause, which spreads by a different route and is less about casual household spread.
There’s no perfect “clearance” test for most home cases. Use judgment: symptom-free for 48 hours and feeling decent is a reasonable bar for returning to normal routines.
When to see a doctor
Most food poisoning is something you manage at home. But it’s worth a medical visit — and a prompt one, sometimes an ER — if you see any of these:
- Signs of dehydration: very dark or infrequent urine, dizziness or lightheadedness when standing, dry mouth, unusual fatigue, or a fast heartbeat. This is the most common reason food poisoning becomes a bigger problem, and it’s the one that can escalate quietly.
- Blood in your vomit or stool, or stools that look black and tarry
- A fever above about 102°F (39°C), or a fever that persists
- Severe or worsening abdominal pain, especially lower-right sided
- Symptoms lasting more than a week
- Vomiting so severe you can’t keep fluids down
- If you’re pregnant, elderly, very young, or have a weakened immune system
Key takeaway: The single most important warning sign is dehydration. If you can’t keep fluids down, or you get dizzy when you stand up, that’s the moment to call a doctor or head to urgent care — not the moment to “try one more hour.”
If dehydration signs appear — dark urine, dizziness on standing, a pounding or racing heart — don’t wait for them to compound. Seek medical attention the same day, and if you can’t keep even sips of fluid down, go in sooner.
Frequently Asked Questions
How do I know if it’s food poisoning or a stomach bug?
Honestly, from the outside it’s hard to tell them apart — both cause nausea, vomiting, and diarrhea. The clue that tips toward food poisoning is a clear link to a specific meal, or several people in the same household getting sick from the same food within a similar window. A single meal that makes one or two people ill usually points to the food.
How long does food poisoning last in a baby?
In infants and young children, norovirus and rotavirus can run 3 to 8 days and carry a higher risk of dehydration. Because small bodies lose fluids fast, watch closely for fewer wet diapers, no tears when crying, or unusual sleepiness — and call your pediatrician early rather than waiting out the full course.
Can food poisoning last a week or longer?
Yes. Bacterial causes like Campylobacter, E. coli, and Salmonella can run 5 to 10 days, and parasites can stretch into weeks. If your symptoms are clearly still going after about 7 days, or are getting worse instead of better, that’s a reason to see a doctor rather than keep waiting it out.
Do I need antibiotics for food poisoning?
Usually not. Most cases are viral or resolve on their own, and antibiotics don’t help a virus. Clinicians reserve antibiotics for specific bacterial causes where they clearly help, and sometimes they’re the wrong move — some E. coli strains can actually get worse with antibiotics. Let a clinician make that call based on testing.
Can I prevent food poisoning in the first place?
You can’t prevent all of it, but you can cut a lot of it down. Cook meat and seafood to safe internal temperatures, refrigerate leftovers promptly (within about an hour of cooking), don’t eat food that’s been sitting at room temperature for more than a couple of hours, and wash your hands and surfaces after handling raw meat. That combination removes most of the common household causes.
