Food poisoning is a common illness. It is usually mild, but can become severe and in some cases fatal. Symptoms of food poisoning (such as nausea, vomiting, abdominal cramping, and diarrhoea) may start suddenly (within 48 hours) of having contaminated food or drink, or may be as late as 70 days. These symptoms are affected by many factors including type of contaminant, the amount eaten, age and your overall health.
How long does food poisoning last
Symptoms may progress rapidly, within a few hours or slowly over days to weeks. In most cases food poisoning is not serious, and has a self limiting course (runs its course in 24-48 hours).
Noroviruses a common cause of food poisoning causes mild illness (often termed "stomach flu") with nausea, vomiting, diarrhoea, abdominal pain, headache, and low-grade fever. The symptoms improve within two to three days. Similarly, food poisoning because of most other bacteria and virus improves in a few days (2-3 days). However, all infections do not have this good prognosis and short course of illness. Some infections such as that of Hepatitis A virus can cause symptoms which may last for about two months. Some cases can have even more prolonged illness or relapse for up to six months.
Food poisoning because of toxins can have a short or prolonged course. Ciguatera poisoning caused by consumption of fish that contains toxins produced by marine algae may cause prolonged symptoms. In many cases, symptoms improve in days or weeks, but in some they may persist for years. Scombroid toxin which is transmitted in seafood (mostly mahi-mahi and tuna) or Swiss cheese causes symptoms for a short period of time. The symptoms may last from four to six hours, and rarely more than one or two days.