In the present case report, cascara sagrada (CS) has been associated with the development of cholestatic hepatitis, complicated by portal hypertension. CS is a mixture of ingredients, among which is anthracene glycoside–an herbal agent that previously has been associated with chronic hepatitis. The liver injury in the case herein reported is believed to be related to either anthracene glycoside or one of the other constituents of CS.
– Am J Gastroenterol 2000 Dec;95(12):3634-7 — Cascara sagrada-induced intrahepatic cholestasis causing portal hypertension: case report and review of herbal hepatotoxicity. — Nadir A, Reddy D, Van Thiel DH.

Cascara sagrada is a new etiologic agents of IgE-mediated occupational asthma and rhinitis. The present study also serves to alert physicians to the risks associated with work in pharmacies devoted to manual preparation of plant extracts, emphasizing the importance of the use of protective measures in these environments.
– Ann Allergy Asthma Immunol 1997 Nov;79(5):449-54 — Occupational respiratory allergic disease induced by Passiflora alata and Rhamnus purshiana. — Giavina-Bianchi PF Jr, Castro FF, Machado ML, Duarte AJ.

Short term use may cause cramps and long term use can cause disturbance of electrolyte balance, esp. potassium deficiency, which, with abuse, can lead to disorders of heart and muscle function (CE).
– Herbal Medicine: Expanded Commission E Monographs.– Blumenthal, Mark; Goldberg, Alicia; Brinckmann, Josef, Eds,; Tyler, VarroE, PhD, ScD.

Can interact unfavorably with prescription medications.