Food poisoning can occur when a person eats or drinks food contaminated with certain types of bacteria, viruses, or parasites. Food can be contaminated during processing, growing, and handling or through dirt, dust, and water found in the environment.

Food poisoning causes symptoms of nausea, vomiting, stomach pain, and diarrhea, usually within 48 hours of eating the contaminated food. The symptoms of food poisoning are often caused by chemicals (toxins) released by the infecting bacteria. Food poisoning may spread if a person comes into contact with stool from an infected person.

Safe food preparation, such as cooking foods thoroughly, storing them properly, and hand-washing before preparing food can help prevent food poisoning.

Examples of bacteria types that may cause food poisoning include salmonella, shigella, campylobacter, and E. coli. Viruses that may cause food poisoning include noroviruses. Parasites that may cause food poisoning include Toxoplasma gondii.

Botulism is a rare form of food poisoning that can be caused by eating foods that were not canned properly.