Non-medical nurse prescribing in the UK continues to evolve with new legislative frameworks. Studies evaluating patterns of prescribing by nurses remain scarce. This secondary data analysis of national prescribing data investigated the prescribing behaviours of community-based nurses and general practitioners (GPs), using constipation as a case study. Currently, 37 683 registered nurses, midwives and health visitors are qualified to independently prescribe in the UK; however, only 16.6% of nurses prescribed items for constipation. Prescribing practices differed between nurses employed by primary care trusts (PCTs) and general practice, between nurses and GPs, and across regions. PCT-employed nurses undertook 83% of nurse prescribing although activity increased steadily among general practice-employed nurses. Pharmacological treatment choices differed between nurses and GPs. Over 60% of all nurses predominantly prescribed from one class of laxative compared with a wider range prescribed by GPs. The extent, impact and outcomes of medical prescribing need further study.