Cascara Sagrada is a natural laxative and colon cleanser that provides gentle overnight relief of mild constipation.  Today, numerous over-the-counter laxatives feature cascara sagrada as a key ingredient. To work properly, the bark must be carefully prepared--cured for at least one year or heated and dried to speed up the aging process. Aging is essential because the fresh bark is very irritating to the gastrointestinal system, causing vomiting and intestinal spasms.