Cascara Sagrada comes from the bark of the buckthorn tree. It stimulates your colon to produce stronger contraction than normal. When it does this, it can work on the most difficult and chronic cases of constipation.It is one of the herbal constipation remedies with a strong laxative effect. It will be found in many herbal combinations that are mixed for constipation. Cascara has Chrysophanic acid, which stimulates your colon wall to produce peristaltic action. Cascara also contains a chemic.