Over-the-counter laxatives for constipation: Use with caution

Laxatives can help relieve and prevent constipation. But not all laxatives are safe for long-term use. Overuse of certain laxatives can lead to dependency and decreased bowel function.

By Mayo Clinic Staff

If you've experienced the discomfort of constipation, you may have tried over-the-counter laxatives. A number of factors — including a poor diet, physical inactivity, pregnancy, illness, travel and some medications — can disrupt normal bowel function and cause constipation. However, laxatives may not be the solution.

Before trying laxatives

How often you have a bowel movement varies, but people normally have as many as three bowel movements a day to as few as three a week. You may be constipated if you have fewer bowel movements than are normal for you. In addition, constipation may involve stools that are difficult to pass because they're hard, dry or small.

However, before turning to laxatives, try these lifestyle changes to help with constipation:

  • Eat fiber-rich foods, such as wheat bran, fresh fruits and vegetables, and oats.
  • Drink plenty of fluids daily.
  • Exercise regularly.

Lifestyle improvements relieve constipation for many people, but if problems continue despite these changes, your next choice may be a mild laxative.

How laxatives relieve constipation

Laxatives work in different ways, and the effectiveness of each laxative type varies from person to person. In general, bulk-forming laxatives, also referred to as fiber supplements, are the gentlest on your body and safest to use long term. Metamucil and Citrucel fall into this category.

Stimulant laxatives, such as Dulcolax and Senokot, are the harshest and should be used only occasionally.

Here are some examples of types of laxatives. Even though many laxatives are available over-the-counter, it's best to talk to your doctor about laxative use and which kind may be best for you.
Type of laxative (brand examples) How they work Side effects
Oral osmotics (Milk of Magnesia, Miralax) Draw water into the colon from surrounding body tissues to allow easier passage of stool Bloating, cramping, diarrhea, nausea, gas, increased thirst
Oral bulk formers (Benefiber, Citrucel, FiberCon, Metamucil) Absorb water to form soft, bulky stool, prompting normal contraction of intestinal muscles Bloating, gas, cramping or increased constipation if not taken with enough water
Oral stool softeners (Colace, Surfak) Add moisture to stool to allow strain-free bowel movements Electrolyte imbalance with prolonged use
Oral stimulants (Dulcolax, Senokot) Trigger rhythmic contractions of intestinal muscles to eliminate stool Belching, cramping, diarrhea, nausea, urine discoloration
Rectal stimulants (Bisacodyl, Pedia-Lax, Dulcolax) Trigger rhythmic contractions of intestinal muscles to eliminate stool Rectal irritation, stomach discomfort, cramping

Oral laxatives may interfere with your body's absorption of some medications and nutrients. Some laxatives can lead to an electrolyte imbalance, especially after prolonged use. Electrolytes — which include calcium, chloride, potassium, magnesium and sodium — regulate a number of body functions. An electrolyte imbalance can cause abnormal heart rhythms, weakness, confusion and seizures.

Jun. 06, 2014 See more In-depth