Senna, an herb used for centuries to restore regular bowel movements, has been approved by the U.S. Food and Drug Administration, or FDA, for use as an over-the-counter laxative. Senna is generally considered to be a safe herbal supplement that produces few side effects, but the herb may cause digestive complaints and electrolyte imbalance, especially when taken incorrectly. Although senna is available without a prescription, you may achieve the safest, most effective results by working with your health-care provider to determine a healthy dose of this herbal product. The FDA has not approved the use of senna for any purpose other than the relief of constipation.
Forms
Many species of the senna plant -- a woody shrub native to the Middle East, South Africa and India -- have laxative properties. The fruit and the leaf of the plant serve as short-term herbal remedies to relieve hard, infrequent stools. Senna fruit may have a more gentle laxative effect and produce fewer adverse reactions than senna leaf. Standardized doses of senna are available in the form of tablets, liquids and powders. Pharmaceutical preparations of the herb may be combined with other laxatives or stool softeners to enhance the effects of senna and make hardened digestive wastes easier to pass. Consult your health-care provider before taking senna with stool softeners or other laxatives.
Gastrointestinal Effects
Senna is a stimulant laxative, which prompts bowel movements by irritating the colon lining and triggering contractions in your intestinal muscles. Increased intestinal activity may cause abdominal cramps, diarrhea, nausea, gas and bloating. MedlinePlus cautions that people with heart disease, inflammatory bowel disease, inflammatory stomach conditions, hemorrhoids, a history of intestinal blockage or abdominal pain should not take senna in order to avoid serious health complications. If you have unexplained abdominal pain before or after taking senna, consult your health-care provider immediately.
Health Risks
Although senna is considered safe for most adults and for children over the age of 2, long-term use of this herbal supplement may cause chronic diarrhea, which may result in dehydration and hypokalemia, or low levels of potassium in your blood. During episodes of diarrhea, you can lose potassium, an electrolyte that regulates heart, nerve and muscle activity. Low potassium levels may cause an irregular heartbeat, muscle weakness, fatigue and confusion. Prolonged diarrhea may interfere with the actions of certain heart medications, blood thinners and medications that relieve water retention.
Recommendations
Before taking senna, ask your health-care provider about the safest dosage for your age and health condition, especially if you are pregnant or breastfeeding. Using senna for more than two weeks may condition your body to become dependent on the laxative rather than following natural bowel patterns. MedlinePlus notes that doses of 17.2 mg daily have been used safely in clinical trials in adults and children ages 12 and older; however, doses over 34.4 mg per day may be unsafe in all populations. If you continue to have hard stools after taking senna according to your health-care provider's instructions, consult your provider for further medical evaluation.
References
- MedlinePlus; Senna; Nov. 10, 2010
- University of Maryland Medical Center; Constipation; Steven D. Ehrlich, N.M.D.; Nov. 20, 2009
- Drugs.com; Senna-Gen (Senna) Medical Facts; Dec. 15, 2010
- Drugs.com; Complete Senna Information; May 31, 2011
- Merck Manuals Online Medical Library; Disorders of Potassium Concentration: Fluid and Electrolyte Metabolism; J.L. Lewis, M.D.; May 2009
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