castor oil /kas″tər/ [L, beaver, oleum, olive oil] , an oil derived from Ricinus communis, used as a stimulant cathartic. ▪ INDICATIONS: It is prescribed as a cleansing preparation of the bowel or colon before examination and, rarely, for constipation. ▪ CONTRAINDICATIONS: Symptoms of appendicitis, intestinal obstruction or perforation, and fecal impaction prohibit its use. It is not to be used during menstruation or pregnancy. ▪ ADVERSE EFFECTS: Among the most serious adverse reactions are rectal bleeding and laxative dependence. Nausea, abdominal cramps, and dizziness also may occur.
