Allergic skin rash, breathing difficulties, fever, sore throat & mouth. 250-mg gastro-resistant tab/supp: Rarely, abdominal pain, diarrhoea, flatulence, nausea & vomiting; headache, dizziness; chest pain, breathlessness or swollen limbs; photosensitivity. 500-mg gastro-resistant tab/PR granules: Headache. Uncommon: Abdominal pain, diarrhoea, dyspepsia, flatulence, nausea, vomiting; severe abdominal pain; changes in liver function parameters, & in pancreatic enzymes; changes in the number of WBC. Gastro-resistant PR granules: Itching. Supp: Reddish non-elevated, target-like or circular patches on the trunk, often w/ central blisters, skin peeling, ulcers of mouth, throat, nose, genitals, eyes.