Food Poisoning: Signs, Symptoms, and Treatment

Medically Reviewed by Poonam Sachdev on April 25, 2024
Written by Stephanie Watson, Lori M. King, PhD
9 min read

Food poisoning is an irritation or infection in your digestive system that you get from something you eat or drink. It's usually caused by foods or drinks contaminated with viruses, parasites, or bacteria. However, harmful chemicals can also cause food poisoning sometimes.

Usually, food poisoning comes on fast and doesn't last long (often less than a week), and most people get better without treatment. However, for some people, food poisoning lasts longer or causes serious complications.

Anyone can get food poisoning, but the groups of people more likely to get food poisoning include:

  • Older adults
  • Infants and children
  • Pregnant people
  • People with weakened immune systems

These groups of people are also more likely to have serious symptoms or complications.

Food poisoning vs. stomach flu

Stomach flu usually results from a virus that you get from someone who is infected with it. In contrast, you usually get food poisoning when you eat food that wasn't cooked long enough or that sat out of the fridge for too long.

Both cause symptoms such as nausea, throwing up, and diarrhea. But there are a couple of different clues about which is causing your symptoms. One way is by how quickly your symptoms start. Food poisoning usually starts about 2-6 hours after you eat the contaminated food. Whereas, stomach flu generally starts about 1-2 days after you get exposed to the virus. Another way is by how fast you get over it. Food poisoning symptoms are usually short and intense, but stomach flu lasts a few days or longer. Also, stomach flu is less likely to cause symptoms such as fever and chills compared to food poisoning.

The most common symptoms and signs of food poisoning include:

If you have a more serious type of food poisoning (such as botulism or fish/shellfish poisoning), you may also get the following symptoms:

  • Blurred vision
  • Tingling or numbness in your skin
  • Weakness
  • Paralysis

These symptoms are serious, so if you have any of these, you need to go to your doctor or ER.

How soon after food poisoning do you vomit?

Depending on the germ that causes your case of food poisoning, your symptoms may start within about 2-6 hours after you eat the contaminated food. Here are some estimated times between exposure and symptom onset by cause:

How long does food poisoning last?

Food poisoning usually runs its course fairly quickly, so you should feel better within about 12-48 hours.

Several kinds of germs cause food poisoning, including bacteria, parasites, and viruses. Some of the most common germs that cause food poisoning include:

Bacteria

Bacteria grow fast when food is kept at a temperature of 40-140 F. Keep your refrigerator set to colder than 40 F to help prevent food poisoning. Also, cook your food thoroughly (internal temperature above 140 F) because this can kill most bacteria.

The main bacteria that cause food poisoning include:

  • Campylobacter, bacteria found in contaminated or poorly processed foods and drinks
  • Escherichia coli (E. coli), usually found in raw vegetables and undercooked meat
  • Listeria, which can be present in deli meats and soft cheeses
  • Salmonella, typically found in undercooked poultry and raw eggs
  • Staphylococcus aureus, which can also cause staph infections
  • Clostridium, which can cause botulism and may infect home-canned, preserved, or fermented foods
  • Vibrio, which can infect raw or undercooked seafood

Viruses

You can get infected with a virus by drinking unsafe water, washing produce with contaminated water, or eating food prepared by someone infected with a virus. Two viruses that cause food poisoning include Norovirus and hepatitis A.

Parasites

You can get parasites from infected food or water. But it's rare to get infected with a parasite in the U.S. because most water is treated. Some parasites that may cause food poisoning include:

  • Toxoplasma gondii, which you can get from cleaning an infected cat's litter box, eating raw or undercooked food, or getting an infected organ in a transplant or blood transfusion
  • Giardia, which you can get from food or surfaces contaminated with human poop
  • Cryptosporidium, which you can get from touching contaminated surfaces or swimming in contaminated water

Another way you may get food poisoning is through eating food containing harmful chemicals, such as:

  • Unwashed produce that has chemical pesticides on their surface
  • Fish or shellfish that has toxins produced by algae or bacteria
  • Some kinds of wild mushrooms

Is food poisoning contagious?

Yes, you can get food poisoning from another person if they have it and don't wash their hands after getting diarrhea or throwing up. You can get sick if you touch surfaces that they touched and then touch your eyes, nose, or mouth. Or if they touch your food without washing their hands.

You're more likely to get food poisoning during pregnancy because your immune system can't fight infections as well as it usually does. Also, your baby's immune system doesn't finish developing until a few months after they are born, so they can't really fight off infections. If you get infected with germs such as listeria, salmonella, or toxoplasma, it can make both you and your baby sick. 

Getting food poisoning when you're pregnant can cause problems with your pregnancy and baby, including:

  • Miscarriage
  • Stillbirth
  • Preterm labor and birth
  • Low birth weight in your baby
  • Life-threatening infections in your baby, such as meningitis (swelling in the brain) or bacteria in their blood
  • Eye infections in your baby
  • Swollen liver and spleen in your baby
  • Jaundice in your baby
  • Seizures in your baby
  • Fluid in your baby's brain

You can help prevent food poisoning by avoiding certain foods, such as:

  • Soft cheeses such as Brie, camembert, chevre, ricotta, feta, mozzarella, bocconcini, and blue-veined cheeses
  • Unpasteurized milk and juice
  • Undercooked or raw meat, fish, or seafood
  • Unwashed and precut fruits and vegetables
  • Soft-serve ice cream
  • Undercooked or raw eggs

You should also avoid leftovers that are more than a day old. Ensure all leftovers have been kept in a refrigerator at less than 40 F and reheated to a high enough temperature (over 140 F).

Some home remedies for food poisoning help ease your symptoms, while others help keep you hydrated.

Stay hydrated

You can lose a lot of fluid in a short time when you're throwing up, having diarrhea, or running a fever. Dehydration can cause you to feel tired and weak, and it may make your heart beat irregularly. It can even be fatal if not treated right away, especially in young kids and older adults.

Staying hydrated is one of the best ways you can support your body while it fights the infection. Try drinking hydration formulas, such as Pedialyte, which can help you stay hydrated better than water. If you have trouble keeping liquids down, you can try sucking on ice chips to stay hydrated. If you get a serious case of dehydration, you may need to go to a clinic or hospital to get fluids through an IV.

Rest your body

Another way to support your body while it fights the infection is to stay home and rest.

Eat bland foods

You may feel too sick to eat on the first day. As long as you are still throwing up, stick to liquids such as water, clear broth, diluted fruit juice, decaffeinated tea, or sports drinks.

But once you are able to eat and drink again, stick to bland foods and eat just a little bit at a time to see how your stomach reacts. The BRAT diet is gentle on your stomach and may help ease your diarrhea because it firms up your poop and replace some nutrients you may have lost through vomiting. BRAT is an acronym for:

  • Bananas
  • Rice
  • Applesauce
  • Toast

Other foods that are gentle on your stomach include dry cereal, saltine crackers, oatmeal, and potatoes. Remember, though, don't eat the BRAT diet for more than a few days at a time because it only gives you a limited amount of nutrition. For instance, it doesn't give you much protein or fiber.

Some foods may make you more dehydrated or increase your nausea and vomiting. Avoid the following until you're feeling well:

  • Dairy products
  • Fried foods
  • Spicy foods
  • Sugary foods
  • Caffeine
  • Alcohol

Take medicine to ease your symptoms

If staying hydrated, resting, and eating a bland diet don't help, you can try easing your symptoms with the help of some over-the-counter medicines, such as:

  • Bismuth subsalicylate (Pepto Bismol, Kaopectate) can help ease nausea and diarrhea
  • Loperamide (Imodium A-D) can help ease diarrhea by slowing down your digestive process

However, these medicines can be dangerous for children. Young children with nausea and diarrhea should instead drink fluids and follow a bland diet. Your pediatrician may also recommend a rehydration solution (such as Pedialyte) to keep them from getting dehydrated.

Add probiotics to your meals

Everyone has bacteria living inside of them. Some of these are helpful, and others can make you sick. You need helpful bacteria, for instance, to digest your food.

Food poisoning can throw off the balance of helpful and unhelpful bacteria in your gut. Probiotics are helpful bacteria such as the ones you already have in your body. Taking these can bring your gut bacteria back into balance, which makes your digestive system healthier and may protect you from food poisoning in the future. Once you're feeling better, you can also eat some yogurt to help keep your gut bacteria in balance.

You can treat most cases of food poisoning at home. However, you should see a doctor if:

  • Your fever goes above 102 F.
  • You see blood in your vomit or poop.
  • Your diarrhea lasts more than 3 days.
  • You're vomiting so often that you can't keep liquids down.
  • You have severe pain.
  • You have signs of severe food poisoning, such as tingling limbs or blurry vision.
  • You have signs of severe dehydration, such as not peeing much or a dry mouth or throat.

If your food poisoning is caused by bacteria or parasites, your doctor may prescribe antibiotics, medicines that target parasites (antiparasitics), or anti-vomiting medicines (antiemetics).

Antibiotics

You usually won't need an antibiotic unless you are very sick or have a high risk of complications, such as blood clots in your kidneys, meningitis, or sepsis. Some antibiotics that your doctor may prescribe (if you're really sick with an E. coli infection) include:

  • Azithromycin (Zithromax, Zmax)
  • Ciprofloxacin (Cipro)
  • Rifamycin (Aemcolo)
  • Rifaximin (Xifaxan)

Antiparasitics

If your food poisoning is caused by a parasite, your doctor may prescribe you an antiparasitic medicine, such as:

  • Metronidazole, tinidazole, furazolidone, or albendazole (for giardia infections)
  • Sulfadiazine plus pyrimethamine, sulfonamides, sulfamethazine, or sulfamerazine (for toxoplasma infections)

Antiemetics (anti-vomiting medicines)

Some medicines your doctor may prescribe to control serious vomiting, include:

  • Chlorpromazine (Thorazien)
  • Metoclopramide (Reglan and Metozolv)

People get food poisoning mainly because they don't store and prepare food safely. To reduce your chances of getting food poisoning:

  • Wash your hands for 20 seconds in hot, soapy water before and after you handle food, especially if you handle raw meat, poultry, seafood, and eggs.
  • Wash raw vegetables and fruits before eating, cutting, or cooking.
  • Clean cooking utensils, cutting boards, dishes, and countertops.
  • Refrigerate or freeze perishable foods such as meat, poultry, seafood, dairy, cut fruit, and leftovers within 2 hours.
  • If you take food out of your fridge or pantry and it looks like it might be spoiled, throw it away.
  • Defrost frozen food in the microwave, refrigerator, or cold water, and cook it right away.
  • Keep raw meat, poultry, and seafood separate from other foods.
  • Use a food thermometer to ensure foods are cooked to a safe internal temperature (over 140 F).

Also, watch out for food recalls. In the U.S., the USDA and FDA issue food recalls when they find out that certain foods are making people sick. Check out foodsafety.gov for the latest recalls.

 

Food poisoning is an illness you get from eating food that's contaminated with bacteria, parasites, or other germs. Usually, symptoms such as vomiting and diarrhea start within hours of eating contaminated food. However, most people get better within a day or two. You can treat food poisoning at home by staying hydrated, resting, and eating foods that are easy on your stomach. To help prevent food poisoning, wash your hands before and after cooking, and make sure to store and cook your foods at safe temperatures.