Plants with Anthraquinones provides a laxative for the large intestine. It creates contractions in the intestinal walls facilitates a bowel movement in about 10 hours from ingestion. The chemical itself is manufactured and widely used as a vat dye used for textiles.
Constipation, textile dye
Aloe, Rhubarb, Senna
I rarely have to use a laxative herb since I've minimized the consumption of carbs. I also tend to eat vegetable that have diuretic properties which cleans my intestines regularly.