The colon, also known as the large intestine, is located in the digestive tract and absorbs water, salts and minerals into the body. The remains of the food then pass into the rectum as feces and are excreted from the body through the anus. Constipation is a condition where stools are hard, dry and difficult to pass from the body. Over-the-counter medications can be used to treat this problem.
Muscle Stimulants
In order for food to pass through your colon, muscle contractions have to take place. When you become constipated, the normal muscle contractions can get stopped, preventing you from having a bowel movement. Stimulants cause rhythmic muscle contractions in your stomach and can promote the movement of stool. Examples of these are Senokot, Correctol, Purge and Dulcolax.
Laxatives
Fiber is a substance that comes in soluble and insoluble forms. It can be found naturally in whole grains, fruits, vegetables and beans. Having a diet low in fiber is one of the risk factors for getting constipation, because fiber promotes regularity by pushing waste matter along in your colon. Bulk-forming laxatives, also called fiber supplements, are over-the-counter formulas that are taken with water to help soften stools and make them easier to pass. Examples of these are Serutan, Citrucel, Metamucil and Fiberall.
Softeners
Stool softeners are specifically designed to moisten hardened stools and make them easier to pass through the colon. They also help prevent dehydration from taking place. Surfak and Colace are two examples of these.
Oil
Lubricants are used to grease the areas around the stool to make it move easily through the intestines. When they are used, bowel movements usually take place in eight hours or less. Examples of these are Fleet and mineral oil.
Saline
Water is an important nutrient to relieve constipation. Saline laxatives promote the passage of hard stools from the colon by attracting water to it like a sponge. These are used in acute cases of constipation. Examples include Haley's M-O and Milk of Magnesia.
