Food poisoning, also called foodborne illness, is illness caused by eating contaminated food. Infectious organisms — including bacteria, viruses and parasites — or their toxins are the most common causes of food poisoning. Food poisoning symptoms, which can start within hours of eating contaminated food, often include nausea, vomiting or diarrhea. Most often, food poisoning is mild and resolves without treatment. But some people need to go to the hospital.
Food poisoning symptoms vary with the source of contamination. Most types of food poisoning cause one or more of the following signs and symptoms:
Signs and symptoms may start within hours after eating the contaminated food, or they may begin days or even weeks later. Sickness caused by food poisoning generally lasts from a few hours to several days.
What causes food poisoning?
Most food poisoning can be traced to one of the following three major causes:
Bacteria is by far the most prevalent cause of food poisoning. When thinking of dangerous bacteria, names like E. coli, Listeria, and Salmonella come to mind for good reason. Campylobacter and C. botulinum (botulism) are two lesser-known and potentially lethal bacteria that can lurk in our food.
Food poisoning caused by parasites is not as common as food poisoning caused by bacteria, but parasites spread through food are still very dangerous. However, people with weakened immune systems and pregnant women risk serious side effects if parasites take up residence in their intestines.
Food poisoning can also be caused by a virus. The norovirus, also known as the Norwalk virus, causes over 19 million cases of food poisoning each year.
To prevent food poisoning at home:
Treatment for food poisoning typically depends on the source of the illness, if known, and the severity of your symptoms. For most people, the illness resolves without treatment within a few days, though some types of food poisoning may last longer.
Treatment of food poisoning may include:
Replacement of lost fluids. Fluids and electrolytes — minerals such as sodium, potassium and calcium that maintain the balance of fluids in your body — lost to persistent diarrhea need to be replaced. Some children and adults with persistent diarrhea or vomiting may need hospitalization, where they can receive salts and fluids through a vein (intravenously), to prevent or treat dehydration.
Antibiotics. Your doctor may prescribe antibiotics if you have certain kinds of bacterial food poisoning and your symptoms are severe. Food poisoning caused by listeria needs to be treated with intravenous antibiotics during hospitalization. The sooner treatment begins, the better. During pregnancy, prompt antibiotic treatment may help keep the infection from affecting the baby.
Antibiotics will not help food poisoning caused by viruses. Antibiotics may actually worsen symptoms in certain kinds of viral or bacterial food poisoning. Talk to your doctor about your options.