Cascara is a strong laxative. 
Cascara is made out of the bark of the Cascara sagrada plant. It is known to stimulate the large intestine and produces a well-documented laxative effect. Cascara also causes water and electrolytes such as sodium and potassium to be expelled with the feces. This eases bowel passage but can also lead to dangerously low potassium and sodium levels if cascara is used for prolonged periods of time.
Scientists have isolated a compound called aloe-emodin from cascara. In laboratory studies, this compound inhibited the growth of tumor cells, but it is unknown if this effect would take place in the human body. Scientists have also studied whether cascara might be a carcinogen, with inconsistent results.
Cascara is one of the ingredients in the Hoxsey herbal therapy, which is promoted to treat cancer. However, there is no evidence that Hoxsey herbal therapy is effective in treating cancer.