The strongest laxatives are stimulant laxatives, according to the Mayo Clinic. These laxatives stimulate the intestinal muscles to contract thus eliminating whatever is in the intestines. Examples of stimulant laxatives include Dulcolax and Senokot. Such laxatives can be bought over the counter and do not require a prescription.
Because these laxatives are so strong, limiting their use is advisable, explains the Mayo Clinic. The stronger medicine has harsher effects on the body. Overuse of laxatives can impede healthy intestinal function. The intestines may not absorb vitamin D or calcium, resulting in weaker bones, according to WebMD. Another harmful effect is that the intestines may become reliant on laxatives to function.
Milder laxatives can be used more frequently. These are often fiber supplements, such as Metamucil or Citrucil, which are bulking agents that allow more water absorption in the intestines. The water absorption enables what is inside the intestines to bulk together, and the greater size moves the material out of the intestines.
Side effects can occur even with the mildest fiber supplement. Before taking a laxative, the Mayo Clinic suggests adding more dietary fiber, exercising and drinking lots of liquids. To add dietary fiber, meals can include fruits, vegetables, whole grains, beans and nuts, explains WebMD.