Question: how long does it take for a laxative work?
Answer: Bulk-forming laxatives can have some effect within 12-24 hours but their full effect usually takes 2-3 days to develop. Osmotic laxatives such as lactulose can take 2-3 days to have any effect so they are not suitable for the rapid relief of constipation. Stimulant laxatives usually work within 6-12 hours.