What should you know about co-amoxiclav diarrhoea?

Antibiotics can alter the balance of organisms in the bowel, leading to loose stools, urgency, cramps, or nausea during treatment or shortly afterwards. Diarrhoea may also have another cause, such as gastroenteritis, food poisoning, food intolerance, coeliac disease, Crohn's disease, giardiasis, or an overactive thyroid. Timing matters: tell a clinician when the antibiotic started, when symptoms began, and whether there is fever, blood, severe pain, or dehydration.

Drink frequent small amounts of fluid and choose simple foods if eating feels difficult. Wash hands carefully after using the toilet and avoid preparing food for others while unwell. Contact the prescriber or pharmacist before stopping, restarting, or changing co-amoxiclav; they can decide whether the infection still needs treatment and whether another explanation needs testing. Avoid anti-diarrhoeal medicines until a clinician advises, particularly if there is fever or blood.

Seek urgent medical help for blood or black stool, severe or worsening abdominal pain, repeated vomiting, fainting, confusion, very little urine, or signs of serious dehydration. Contact a clinician promptly for persistent watery diarrhoea after antibiotics, fever, or marked weakness. Do not wait for routine review if you cannot keep fluids down or feel suddenly much worse.

Could this be an antibiotic effect or another bowel infection? Should I continue co-amoxiclav, and do I need a stool test? How can I replace fluids safely, and which symptoms should prompt urgent review?