Stomach bug types

Gastroenteritis affects the stomach and bowel. Viruses commonly spread through close contact, contaminated hands, food or surfaces; rotavirus infection is one example. Bacteria and toxins from contaminated food can also cause sudden vomiting, diarrhoea and abdominal cramps. Less commonly, parasites or another bowel condition can produce similar symptoms. Symptoms alone cannot always identify the cause, because fever, nausea, loose stools and loss of appetite overlap.

Prioritise fluids, using small frequent sips if nausea or vomiting is present. Rest and return to simple foods as tolerated. Wash hands with soap and water, keep separate towels and avoid sharing food or utensils. Do not use leftover antibiotics or anti-diarrhoeal medicine without professional advice; the right choice depends on the suspected cause and the person’s health. A clinician may ask about travel, food exposures, sick contacts and symptom timing.

Seek prompt care for blood in stool, severe abdominal pain, repeated vomiting, signs of dehydration, confusion, fainting or a concerning fever. Children, older adults, pregnant people and those with weakened immunity may need earlier assessment. A clinician can consider examination or testing when symptoms are severe, prolonged, recurrent or linked to a possible outbreak.

Ask whether your pattern suggests a need for stool testing, how to manage fluids, and whether medicines or recent travel change the treatment plan.