Dulcolax is a brand name for the drug bisacodyl, which is a laxative used to treat constipation. It works by increasing the movement of the intestines, helping the stool to come out. Dulcolax can also be used to clean out the intestines before a bowel examination or surgery. It is known as a stimulant laxative, which means it stimulates the lining of the lower bowel to promote movement and accumulation of water into the bowel to produce soft formed stools. Dulcolax is ineffective in altering the digestion or absorption of calories or essential nutrients in the small intestine. It is important to follow the instructions on the product package or as directed by a doctor or pharmacist when taking Dulcolax. Long-term and excessive use of Dulcolax may cause an imbalance of salts in the body, including low potassium, muscle weakness, kidney problems, and fluid imbalance.