OBJECTIVE--To investigate the role of community pharmacists in providing advice and treatment for children with diarrhoea; to investigate mothers' responses to diarrhoea in their children. DESIGN--Cross sectional questionnaire study of a random selection of community pharmacists and of mothers attending child health clinics. Pharmacists were interviewed and given a questionnaire and a separate group was visited by a researcher posing as a parent; mothers were interviewed at the clinic. SETTING--Newcastle upon Tyne. SUBJECTS--20 pharmacists were interviewed and visits by a researcher posing as a parent were carried out to 10 different pharmacists; 58 mothers were interviewed. MAIN OUTCOME MEASURES--Advice given by pharmacists was contrasted with standard advice on management of diarrhoea in children. RESULTS--Half of the pharmacists interviewed and 70% of pharmacists visited by a researcher posing as a parent recommended inappropriate treatment of childhood diarrhoea (such as antidiarrhoeal drugs and withholding breast milk), and only 30% at interview stated that they would ask for the age of the child. Mothers' knowledge of home treatment was inadequate. All pharmacists in the posed visits recommended a purchased treatment. CONCLUSION--Pharmacists are widely used by parents for consultation for children's ailments but their advice is not always appropriate; hence they should be given more consistent training in recognising and managing clinical problems. Medical advice on management of diarrhoea is also inconsistent and should be modified to conform to the guidelines of the World Health Organisation.