Stimulant laxatives are believed to stimulate nerve endings in the nerve plexuses of the bowel wall, increasing the movement of its content via several mechanisms. The most common active ingredients include the Anthraquinones (Senna, Aloin, Frangula, Cascara and Powdered rhubarb) and the Diphenylmethane derivatives (Bisacodyl, Sodium picosulfate, Phenolphthalein). Traditionally-used castor oil has fallen into disuse because of its ‘drastic’ action and unpleasant taste.