Cascara sagrada, derived from the dried bark of the Rhamnus purshiana tree, has a long history of use as a natural laxative among Native American populations and was later adopted into Western herbal medicine. The primary active compounds in cascara sagrada are anthraquinone glycosides, such as cascarosides, which exert their laxative effect by stimulating peristalsis (the contraction of intestinal muscles) and inhibiting water and electrolyte absorption in the colon, thereby softening stool and promoting bowel movements.

Scientifically, cascara sagrada has been recognized and regulated as an over-the-counter laxative ingredient by the U.S. Food and Drug Administration (FDA) in the past, although concerns about safety and potential for misuse led to its removal from many OTC products in 2002. Several clinical studies and pharmacological reviews support its short-term effectiveness for treating constipation in adults, especially when used for occasional, not chronic, constipation. However, most studies are small, dated, or of limited methodological quality. Adverse effects, such as abdominal cramps, diarrhea, and electrolyte imbalances, are possible, especially with prolonged use.

In summary, cascara sagrada’s use for constipation is both traditionally and scientifically supported, with moderate-quality evidence for short-term efficacy. Long-term use is not recommended due to safety concerns, and it is generally advised to consult a healthcare provider before using cascara sagrada for constipation.