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. Infectious organisms or their toxins can contaminate food at any point of processing or production. Contamination can also occur at home if food is incorrectly handled or cooked. 

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. 

In the case of Hawley Crippen, the unusual poison choice, Hyoscine, led investigators to question the validity of the remains. It seemed unusual for the toxicologist to check immediately for the common alkaloids before looking for more common poisons. But what are the more common poisons used in murders?

As far as the murder of individuals is concerned there are relatively few agents that have been used and of course there is no way of knowing how many people have been deliberately killed this way because no doubt many such deaths were attributed to natural causes.

Mithridatism is the practice of protecting oneself against a poison by gradually self-administering non-lethal amounts. The word is derived from Mithridates VI, the King of Pontus, who so feared being poisoned that he regularly ingested small doses, aiming to develop immunity.