Over-the-counter (OTC) medicines are medicines you can buy without a prescription from your doctor. Laxatives are a type of OTC medicine used to treat constipation. Many different kinds of OTC laxatives are available. Some constipation medicines may be called stool softeners or fiber supplements.
Bulk-forming laxatives add “soluble” fiber to the stool. This causes the stool to absorb more water and creates larger, softer stools. The larger stools help trigger the bowel to contract and move the stools out. Bulk-forming laxatives generally are the safest type of laxative. Examples of bulk-forming laxatives include psyllium (1 brand name: Metamucil), polycarbophil (1 brand name: FiberCon), and methylcellulose (1 brand name: Citrucel). To reduce your risk of side effects, you should start slowly and make sure to drink plenty of fluids while taking bulk-forming laxatives. Gradually increase how much you use.
Lubricant laxatives work by coating the surface of the stools to make them more slippery. This helps the stools move out of the body more easily. Glycerin suppositories lubricate the inside of the anus (the outside opening to the intestine) to make it easier to pass hard stools out of the body.
Stool softeners help mix fluid into stools to soften them. This makes stools easier to pass out of the body. An example of a stool softener is docusate (1 brand name: Colace).
Osmotic laxatives cause the intestine to hold more fluid. This softens stools and helps the bowel move them out. Examples include polyethylene glycol (1 brand name: Miralax) and magnesium hydroxide solution (called milk of magnesia).
Stimulant laxatives are the harshest type of laxatives. They cause the bowel to squeeze or contract to move the stools out. Stimulant laxatives should not be used for more than a few days. When these laxatives are taken for a long time, the bowel can lose its muscle tone and “forget” how to push the stool out on its own. Bisacodyl (1 brand name: Dulcolax) and sennosides (1 brand name: Senokot) are examples of stimulant laxatives.
Most of the time, constipation doesn’t require treatment with laxatives. It will usually go away on its own or if you make changes in your diet and other habits. For example, you can prevent or treat constipation by eating enough foods rich in soluble and insoluble fiber (such as bran, oats, foods made with whole grains, fruits, and vegetables), drinking enough fluids, and getting enough exercise. Sometimes you may need a little help from an OTC laxative.
Read the directions on the drug facts label to learn how much medicine to take and how often to take it. If you have any questions about how much medicine to take, call your family doctor or pharmacist. Keep a record (1-page PDF; About PDFs) of the OTC medicines you are using and when you take them. If you need to go to the doctor, take this list with you.
Follow these tips to make sure you are taking the right amount of an OTC laxative:
Store all medicines up and away, out of reach and sight of young children. Keeping medicines in a cool, dry place will help prevent them from becoming less effective before their expiration dates. Do not store medicines in bathrooms or bathroom cabinets, which are often hot and humid.
Most laxatives don’t have side effects if you use them correctly. However, sometimes they can cause cramping, gas, bloating, nausea, or diarrhea.
Some people, including children and people who have diabetes or kidney disease, are at risk for electrolyte imbalances while taking certain laxatives. Electrolytes are substances in your body that help your nerves, organs, and muscles work properly. Taking laxatives can cause you to eliminate too many electrolytes. When this happens, you may have side effects such as nausea, vomiting, headache, confusion, fatigue, and muscle weakness or spasms. Electrolyte imbalance can be serious, so check with your child’s doctor before giving him or her a laxative. And if you have a chronic condition, be sure to talk to your doctor before taking a laxative.
Don’t take laxatives if you have an allergy to any of the ingredients. Some people may be allergic to psyllium, a key ingredient in 1 type of bulk-forming laxative.
Laxatives aren’t meant for long-term use. Don’t use laxatives for longer than 1 week unless your doctor recommends it. Long-term use or overuse of laxatives can cause health problems. Overusing laxatives may also hide symptoms that are important for your doctor to know about. This could delay finding out about other health problems you have and also delay the treatment you need.
If you have a condition called phenylketonuria, you shouldn’t take a laxative that contains phenylalanine.
Laxatives can get in the way of how your body absorbs certain medicines and some nutrients. In general, don’t take any other medicines within 2 hours of taking a laxative. If you’re taking a prescription medicine of any kind, talk to your doctor before taking a laxative. You also shouldn’t mix different types of laxatives, such as oral laxatives (which you take by mouth) and rectal laxatives (which you take by inserting a suppository or enema into your rectum, which is the last part of your large intestine). Don’t take bisacodyl within 1 hour of taking antacids or drinking milk.
Mineral oil and castor oil are sometimes used as laxatives, but they shouldn’t be used often. If mineral oil is used often, it can cause deficiencies of vitamins A, D, E, and K. Castor oil, which is a stimulant laxative, can lead to chronic constipation because it can cause you to lose muscle tone in your bowel. Mineral oil and castor oil also interact with blood-thinning medicines, antibiotics such as tetracycline, and certain heart and bone medicines.
If you have any of the following symptoms, talk to your doctor before using an OTC laxative:
Stop taking laxatives and call your doctor if you have any bleeding from your rectum or if you don’t have a bowel movement after using a laxative. These could be signs of a more serious problem.
Funding and support for this material have been provided by the Consumer Healthcare Products Association.
Written by familydoctor.org editorial staff