This paper presents a literature review of two commonly used osmotic laxatives, lactulose and polyethylene glycol (PEG). With increasing numbers of nurses in the community being non-medical prescribers, informed decisions on choice of laxatives is required. Nurses who do not prescribe will often have a view for the benefit of their patients. Following a literature search, eight papers were selected for review. The review leads to the conclusion that, while both preparations are useful, PEG is more effective in many instances and should be the laxative of choice unless there are contraindications arising from the assessment of the patient. Non-pharmacological approaches to the management of constipation should be addressed before considering laxative use.