Types of Food Poisoning

Food poisoning is grouped by the germ or toxin that causes it. The type affects how fast symptoms begin and how serious they can be.

Bacterial food poisoning

• Toxin-type (fast onset). Staphylococcus aureus and Bacillus cereus toxins cause vomiting within hours. Usually settles in a day.
• Infection-type. Salmonella, Campylobacter, E. coli, Shigella and Vibrio cholerae cause diarrhoea, cramps and sometimes fever or blood in the stool.
• Serious bacterial types. Listeria can cause severe illness in pregnancy and in people with weak immunity. Clostridium botulinum causes botulism, a medical emergency.

Viral food poisoning

Norovirus, rotavirus and hepatitis A. Norovirus spreads quickly and causes sudden vomiting and diarrhoea.

Parasitic food poisoning

Giardia, amoeba and other parasites, usually from contaminated water. Symptoms can last for weeks and need specific treatment.

Chemical and natural toxin poisoning

• Poisonous mushrooms
• Certain fish and shellfish toxins
• Mould toxins in stored grains and nuts
• Pesticide or chemical contamination

These can be dangerous even when symptoms start with a simple stomach upset.

Travellers' diarrhoea

A common form after eating or drinking unfamiliar food or water in new places.

Ayurvedic naming

Ayurveda describes sudden vomiting and diarrhoea after bad food as visuchika and describes indigestion as ajirna, including forms linked to ama. These terms are traditional and do not match the modern types exactly.

Why the type matters

Most types need only fluids and rest. Some, such as botulism, listeriosis, mushroom poisoning and parasites, need medical treatment, which is why warning signs matter.