Cathartics, also known as laxatives or purgatives, are substances that induce bowel movements and help alleviate constipation. They work by increasing the motility of the gastrointestinal tract or by softening the stool. Cathartics may be prescribed for various conditions, including irritable bowel syndrome, diarrhea, and fecal impaction.

There are several types of cathartics, each with a different mechanism of action. Bulk-forming agents are natural or synthetic substances that form a gel-like mass in the intestine, increasing the bulk of the stool and promoting peristalsis. Examples include psyllium, methylcellulose, and polycarbophil.

Osmotic agents, such as magnesium citrate, lactulose, and polyethylene glycol, work by drawing water into the bowel, causing the stool to soften and become easier to pass. Lubricant cathartics, such as mineral oil, coat the stool and the intestine, making it easier to move through the colon.

Stimulant cathartics, such as senna, bisacodyl, and cascara, increase the motility of the intestine by stimulating the nerve endings in the bowel lining. Chloride channel activators, such as lubiprostene, work by increasing the secretion of chloride ions into the intestine, which leads to the secretion of water and softening of the stool.

Cathartics can be taken orally or rectally and are available in various forms, including tablets, capsules, powders, liquids, and suppositories. While cathartics can be useful in relieving constipation, misuse or overuse can lead to electrolyte imbalances, dehydration, and bowel damage. It is important to use cathartics only as prescribed by a healthcare provider and to follow their instructions carefully.