Laxatives take varying amounts of time to work depending on the type:

• Suppository laxatives act the fastest, typically within 15 to 30 minutes.
• Stimulant laxatives take about 6 to 12 hours.
• Lubricant laxatives take 6 to 8 hours.
• Bulk-forming laxatives start working in 12 to 24 hours with full effect up to 72 hours.
• Emollient (stool softener) laxatives can take 12 to 72 hours.
• Hyperosmotic laxatives differ: saline types act within 30 minutes to 6 hours, lactulose takes 48 to 72 hours, and polymer types take 6 hours or more.

Overall, most laxatives begin to work within a few hours to a couple of days, with suppositories providing the quickest relief and bulk-forming or emollient laxatives taking longer to have full effect.