Laxatives are simply things consumed in an attempt to loosen stools and treat constipation. They can be drugs, foods, or compounds. Laxatives work by hastening elimination of undigested food in the colon and large intestine.
There are several different kinds of laxatives, some are natural and others are not...
Vegetables and foods - Certain foods and vegetables have shown to be effective laxatives and can be taken to help relieve constipation. Some of these include dates, apple juice, beets, chicory, almonds, endive, coconut, chocolate, grapes, coffee, chicken broth, flaxseed, liquorice, mangos, papayas, molasses, olives, prunes, plums, pineapple, and walnuts.
Bulk-producing agents - Bulking agents bulk the tool and cause it to retain more water. They also form a gel which makes it easier to pass along and should be consumed with lots of water. These are typically very gentle and can be taken regularly with no negative or unwanted side effects. Some examples of these bulking agents include psyllium husk, methylcellulose, apples, dietary fiber, and polycarbophil.
Stool softeners - Stool softeners such as docusate cause fat and water to penetrate the stool and makes them easier to pass. If used on a regular basis, stool softeners can become ineffective as the body develops a tolerance for them.
Lubricants - Lubricants have one job, to make the stool slippery and easier to pass. Mineral oil is a great example of a lubricant.
Hydrating agents - Hydrating agents help the intestines to hold water which softens the stool.
Stimulants and irritants - Laxatives such as Ex-lax can be dangerous and prolonged use can lead to a cathartic colon. Stimulants are the most severe of all laxatives and should generally be used in emergency conditions.