The poisoning occurs after ingesting poisonous species of mushrooms or plants or contaminated fish or shellfish.
The most common symptoms are diarrhea, nausea, and vomiting and sometimes seizures and paralysis.
The diagnosis is based on symptoms and examination of the ingested substance.
Avoiding wild or unfamiliar mushrooms and plants and contaminated fish reduces the risk of poisoning.
Replacing fluids and ridding the stomach of the toxic substance are the best forms of treatment, but some substances are deadly.
(See also Overview of Poisoning.)
Many disorders cause sudden vomiting and diarrhea due to inflammation of the digestive tract (gastroenteritis). Sometimes people loosely refer to all of these disorders as "food poisoning." However, most vomiting and diarrhea is caused by a digestive tract infection from a virus or bacteria.
Only gastroenteritis caused by a toxin that was eaten is true food poisoning. For example, bacteria in contaminated food can produce such toxins (see Staphylococcal Food Poisoning). Also, although many poisonous plants, mushrooms, and seafood affect the digestive tract, some affect other organs.
Gastroenteritis may also affect people who have ingested foods contaminated by external toxins, such as
Most people with food poisoning recover fully and rapidly with nothing more than replacement of fluids and electrolytes. As soon as symptoms begin, a person should try to consume large amounts of fluids. If fluids cannot be tolerated, the person needs to go to an emergency department for intravenous fluids.
If possible, it is often a good idea to rid the stomach of the toxic substance as quickly as possible. For most people, vomiting accomplishes this task.
Specific treatments are sometimes given when the toxin is known.