How fast do oral laxatives work?

The time it takes for an oral laxative to work depends on the type of laxative. Saline laxatives – 1/2 to 3 hours,   Stimulant laxatives – 6-12 hours,   Osmotic laxatives – 1/2 to 72 hours,   Stool softeners – 24 – 48 hours,   Fiber-based laxatives – 12 to 72 hours,   Lactulose – 24 – 48 hours and Polyethylene glycol – 48 – 96 hours.