Senna is a type of shrub native to North Africa, the Middle East and parts of Asia. Many species of senna are used medicinally, particularly to combat constipation. Many naturopaths, herbalists and practitioners of traditional Chinese medicine consider senna leaves to be powerful natural laxatives and inappropriate for regular use. Senna is best used for short periods of time and only for serious bouts of constipation. Senna leaf is available as an herbal tea, a liquid extract or in capsules and tablets.
Senna leaves and seeds are rich sources of anthroquinone glycosides, which are compounds that stimulate the large intestine to contract. They work by slightly irritating the lining of the colon, which leads to bowel-muscle contraction and more frequent bowel movements. As such, senna leaves are relatively common ingredients in over-the-counter laxatives. Senna also causes less water to be absorbed from your large intestine, which leads to softer stools that are easier to pass. Chronic constipation is painful and can become a health hazard due to the toxins that are produced by compacted fecal material. Waste material can become trapped in the large intestine, which is why senna is also used as an herbal colon-cleansing agent.
Senna contains essential oils, tannins and other compounds that help deter the growth and proliferation of microorganisms such as bacteria, fungi and parasites. Senna leaf can be made into a paste and applied to various skin conditions such as acne, ringworm and mild abrasions. Senna leaf can also be chewed like tobacco to combat mouth infections and gingivitis. Senna is also a mild anti-inflammatory that can soothe internal and external swelling.
Products containing senna leaf or seed should not be used for more than a week or so at a time. Continual use of senna can lead to lazy bowel syndrome, where the bowel becomes reliant on chemical stimulation, or chronic diarrhea and dehydration. Short-term use of senna can also lead to unpleasant side effects such as abdominal cramping, intestinal pain, bloating, flatulence, nausea, electrolyte imbalance and edema. Avoid senna leaf if you have diverticulitis, ulcerative colitis, Crohn's disease or severe hemorrhoids. Consult your doctor before using senna leaf, especially if it's for more than a few days.
Senna is probably not the best herbal remedy to use initially for a mild case of constipation. Other natural laxatives such as cascara sagrada are gentler on your bowels and lead to fewer side effects. Senna is a reliable last resort for severe cases of constipation and typically triggers bowels movements within eight hours or less. To reduce unpleasant side effects, especially flatulence, combine senna with other herbs such as peppermint, fennel or ginger.
- PDR for Herbal Medicines; PDR Medical Staff
- Natural Standard Herb & Supplement Reference: Evidence-based Clinical Reviews; Catherine E. Ulbricht and Ethan M. Basch
- Principles and Practice of Phytotherapy: Modern Herbal Medicine; Simon Mills and Kerry Bone
Sirah Dubois is currently a PhD student in food science after having completed her master's degree in nutrition at the University of Alberta. She has worked in private practice as a dietitian in Edmonton, Canada and her nutrition-related articles have appeared in The Edmonton Journal newspaper.