What should you know about B cereus food poisoning?

Bacillus cereus can multiply in food left at unsafe temperatures, including cooked rice, pasta and other starchy dishes. One toxin pattern tends to cause nausea and vomiting soon after eating; another more often causes watery diarrhoea and abdominal cramps later. Fever may occur, but it is not required. Symptoms usually settle as the body clears the toxins, although the illness can become serious when vomiting or diarrhoea causes dehydration.

Take frequent small sips of water or oral rehydration solution. If nausea is strong, try a spoonful at a time and increase gradually. Rest, then return to plain foods as tolerated. Avoid alcohol and very fatty meals while the stomach is unsettled. Do not eat food that may have caused the illness, and wash hands carefully to reduce spread. Oral rehydration therapy can help replace water and salts; severe dehydration may need IV fluid therapy.

Get urgent medical help for inability to keep fluids down, very little urine, marked drowsiness, fainting, confusion, blood in stool or vomit, severe abdominal pain, or breathing difficulty. Seek advice sooner for an infant, older adult, pregnancy, or a person with a significant long-term illness. Fever that is high or persistent, or diarrhoea that is not easing, also warrants assessment.

Ask whether your symptoms fit food poisoning, how much fluid to take, whether testing is useful, and which medicines should be avoided while vomiting or diarrhoea continues.