Diseases & Conditions

Food Poisoning

Food poisoning, also referred to as food-borne illness, is a result of eating contaminated food. Infectious organisms — including various bacteria, viruses and parasites — or their toxins are the most common cause of food poisoning.

Infectious organisms can contaminate food at any point during its processing or production. Contamination can also occur at home if food is incorrectly handled, improperly cooked or inadequately stored. Illness is not inevitable after you eat contaminated food. The effects depend on the contaminant, the degree of contamination, your age and your health.

Food poisoning symptoms vary with the source of contamination. Most types of food poisoning cause one or more of the following signs and symptoms:

• Nausea
• Vomiting
• Watery diarrhea
• Abdominal pain
• Stomach cramps
• Loss of appetite
• Fatigue
• Fever

Signs and symptoms may start within hours after eating the contaminated food, or they may begin days later. Sickness caused by food poisoning generally lasts from one to 10 days.

When to see a doctor
If you experience any of the following signs or symptoms, seek medical attention.

• Frequent episodes of vomiting for more than two days
• Vomiting blood
• Inability to keep liquids down for 24 hours
• Severe diarrhea for more than three days
• Blood in your bowel movements
• Extreme pain or severe abdominal cramping
• An oral temperature higher than 101.5 F (38.6 C)
• Signs or symptoms of dehydration — excessive thirst, dry mouth, little or no urination, severe weakness, dizziness or lightheadedness

If you suspect food poisoning, contact your local health department. Your report can help the health department identify a potential outbreak and may help prevent other people from getting sick. Besides listing your symptoms, you may need to recall what you ate, where you got the food and when you got sick.

Food poisoning is often diagnosed based on a detailed history, including how long you've been sick, characteristics of your symptoms and specific foods you've eaten. Your doctor will also perform a physical exam, looking for signs of dehydration.

Depending on your symptoms and health history, your doctor may conduct diagnostic tests, such as a blood test, stool culture or examination for parasites, to identify the cause and confirm the diagnosis. For a stool culture, your doctor will ask for a stool sample and send it to a laboratory, where a technician will try to grow and identify the infectious organism. In some cases, the cause of the food poisoning cannot be identified.

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 a week or more.

The primary goals of treatment are to replace lost fluids and to relieve symptoms of severe diarrhea and vomiting. 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.

Children and adults who are severely dehydrated need treatment in a hospital, where they can receive salts and fluids through a vein (intravenously), rather than by mouth. Intravenous hydration provides the body with water and essential nutrients much more quickly than oral solutions do.

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 in the hospital. And the sooner treatment begins, the better. During pregnancy, prompt antibiotic treatment may help keep the infection from affecting the baby.