Food Poisoning: How Long It Lasts + What to Do When You’ve Eaten Something Bad

Most cases of foodborne illness will pass on their own
Salmonella Bacteria

Turns out, taking a chance on those leftover chicken salad sandwiches that had been sitting out on the free table at work all day wasn’t such a great idea.

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Now you’re home with dreaded food poisoning, splitting time between the couch and the bathroom.

While we think of food poisoning, or foodborne illness, as one thing, it’s actually a broad term that encompasses more than 250 kinds of disease-causing germs, including Salmonella, E. coli and rotavirus. And those germs can cause varying degrees of nausea, diarrhea and vomiting, depending on a number of factors.

Gastroenterologist Christine Lee, MD, answers some commonly asked questions about how to get through a bout of food poisoning.

Q: How do you get food poisoning?

A: You get food poisoning from eating or drinking food that is contaminated with pathogenic viruses, bacteria, toxins, parasites or toxic chemicals. It doesn’t always come from rotten or spoiled food. It could come from perfectly good food that was just improperly handled or cooked.

Q: How long does it take food poisoning to set in after you eat something contaminated?

A: It depends on what the culprit is, how much was consumed and a person’s individual immune system. For example, common food poisoning like Bacillus cereus can set in within 6 to 16 hours. But there are some foodborne illnesses that are latent, meaning they have to reproduce in your system and get into a large load. Hepatitis A virus, for example, can take 15 to 50 days to present.

But in general, most common types take 4 to 24 hours to set in.

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Q: How long does food poisoning last?

A: That also depends on the individual. In general, 1 to 10 days, but it can be longer in some circumstances.

Q: Can food poisoning give you a fever?

A: Yes, viral or bacterial food poisoning can sometimes produce fever.

Q: What should you eat during food poisoning?

A: It’s best to stick to a BRAT diet. That would be things like bread, rice, rice pudding, applesauce, toast and bananas. Something bland. Or chicken noodle soup.

You want to stay away from food that is more challenging for your digestive track to digest, like greasy, fried or spicy foods.

You want to drink lots of fluids, and not just water. Water is isotonic. If you’re ill and you’re losing a lot of water through diarrhea, or if you have a fever and you’re sweating, the best replenishment isn’t exactly water. It really should be a not-isotonic fluid. That would be something with salt, sugar or electrolytes in it, like Gatorade, broth, ginger ale or juice. When you consume that kind of fluid, you tend to keep it in your body — it’s less likely to just run off or go straight to your kidneys where you’ll urinate it out or you have diarrhea output.

Consult your physician if you have a medical condition that limits your sodium consumption, such as heart, liver or kidney disease.

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Q: What can you take for food poisoning?

A: Bismuth subsalicylate (Pepto Bismol®) is generally fine to take. It has soothing and anti-inflammatory effects. But be aware that it will turn your stool to black due to the bismuth. (This is normal but can be alarming if you’re not expecting it!)

I would not recommend taking something like loperamide (Imodium®) to stop diarrhea, as it’s better to expel the toxin out of your system rather than keeping it in.

Q: Should you go to the doctor if you have food poisoning?

A: For most of us with healthy immune systems, we can usually recover from food poisoning on our own. As long as you’re able to keep food or liquids down, then you can try to hydrate at home and let it run its course.

But if your nausea is so severe that you’re unable to keep any fluids down, you need to seek medical help. IV fluids can be administered for hydration and to replete lost electrolytes. You should also see a doctor if you develop a high fever, bloody diarrhea or extreme pain.

For people who are on immunomodulating drugs or medications that suppress the immune system, or who have medical conditions that suppress the immune system, I recommend seeking immediate medical attention.

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