Why does typhoid fever cause diarrhoea?

Typhoid fever is an infection caused by Salmonella Typhi. After entering through contaminated food or water, the bacteria can affect the intestinal lining. An irritated lining may release more fluid into the bowel and absorb less water from its contents, so stools become loose or frequent. Diarrhoea is a common presentation of Typhoid Fever, but loose stools also have many other causes.

Some people instead develop constipation early in the illness. Fever, tiredness, headache, abdominal discomfort, reduced appetite and diarrhoea can occur together, and the overall pattern helps a clinician assess the cause.

Arrange medical assessment promptly if typhoid fever is possible, especially after travel or exposure to unsafe food or water. A clinician may request samples or blood tests and prescribe treatment when appropriate. Sip safe fluids regularly; oral rehydration solution may help replace water and salts lost in stools. Eat small, plain meals as tolerated and wash hands carefully after using the toilet.

Do not start leftover antibiotics or medicines intended for someone else. Taking the wrong treatment can complicate assessment and may not treat the infection.

Seek urgent medical help for confusion, fainting, severe or worsening abdominal pain, repeated vomiting that prevents drinking, very little urine, marked weakness, black stools, or visible blood in stool. These signs can point to dehydration, bleeding, or another serious bowel problem. Children, older adults, pregnant people and anyone with a weakened immune system should be assessed early when fever and diarrhoea develop.

Ask whether your symptoms and recent travel or food exposures fit typhoid fever, which tests are useful, how to prevent dehydration, and when you can safely return to work or food preparation. If treatment is prescribed, ask what changes should prompt a review.