Final answer:
Laxatives are a group of drugs used to promote defecation, particularly to treat and prevent constipation. They work by various mechanisms such as softening stools, adding bulk, and stimulating muscle contractions. Before using laxatives, increasing fiber and water intake is advisable.
Step-by-step explanation:
A common group of drugs that are used to promote defecation are termed laxatives. Laxatives are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation, a condition where the stools become hard and difficult to pass, leading to infrequent bowel movements. Laxatives work in various ways: some add bulk to the stool, some soften the stool by increasing water content, and others stimulate bowel muscle contractions. Food residue is concentrated and stored in the colon before it is eliminated through defecation, and mucus plays a role in easing the passage of feces. During the defecation process, mass movements push feces from the colon into the rectum, which can be aided by voluntary actions such as the Valsalva's maneuver. It's crucial for individuals who experience constipation to increase their dietary fiber intake and water consumption before resorting to laxatives, and these should only be used under a doctor's supervision as they can be habit-forming.