Senokot® Before Bed. The gentle effects of Senokot® Tablets' direct action on the large intestine are generally felt 6-12 hours after ingesting. Take at bedtime (or as required) for more natural morning results. 00:07 - Don't let occasional constipation stop you. 00:10 - For effective overnight relief, trust Senokot, a natural laxative made from Senna.