Based on a survey of 130 pharmacies and patent medicine shops in Borno State, Nigeria, this study documented and analysed what retail pharmacies prescribed for acute childhood diarrhoeas. It related their knowledge of appropriate prescriptions for watery diarrhoea with their actual prescriptions. The study found that appropriate knowledge was not reflected in appropriate prescribing. Those with appropriate knowledge, as well as those without such knowledge, routinely prescribed drugs instead of oral rehydration therapy (ORT) for watery diarrhoea. The motivations for such inappropriate prescribing were identified as the factors to be addressed in interventions aimed at improving prescribing.