Senna

Senna (Senna alexandrina) is a stronger laxative than psyllium. This stimulant laxative is a mix of the dried fruits and leaves of the plant, which contain sennosides and anthraquinones, both known to increase bowel movement. The sennosides break down into rhein anthrones in the large intestine, which then irritate the nerve endings there and stimulate powerful contractions. They also increase water pressure inside the colon. Together, these lead to steady bowel movement.


Senna tea is an example of ancient remedies that still work wonders, the first recorded use dating back to the 9th century. It belongs to a special group of laxatives called stimulant laxatives. Senna tea is more potent than psyllium husk in clearing up a clogged bowel.

The preparation of senna that is used to treat constipation is a mix of the dried fruits and leaves of a flowering plant called – no surprises there – senna. Of the many species of senna, the most popularly used varieties are Tinnevelly senna (Cassia angustifolia), which grows in India, and Alexandrian senna (Cassia acutifolia), which grows in some parts of Africa.

The leaves and the fruits of senna contain:

  • Glycosides like sennosides A to E – sennosides A and B are the most bioactive
  • Anthraquinones like aloe-emodin, emodin, chrysophanol, physcion, – aloe emodin is present in the yellow latex in the aloe leaf
  • Anthracenones like racemochrysone and dihydroanthracenone
  • Flavonoids like kaempferol, isorhamnetin,
  • Plant sterols (fats) like beta-sitosterol and stigmasterol

Why It’s So Great

The most prominent use of senna is as a laxative, thanks to the sennosides in it. The sennosides are not affected by the digestive acids in the stomach or the digestive enzymes in the small intestine. They pass unabsorbed into the large intestine, where they are broken into rhein anthrones. The rhein anthrones are the main players in this game.

  • Increases peristalsis: Peristalsis is the special wave-like motion that helps food pass down your digestive tract, right from the food pipe to the large intestine. Rhein anthrones in senna irritate the nerve endings in the lumen (the inside walls of the colon), which then send a signal for contraction of the smooth muscles of the intestine. As contractions increase, so does peristalsis, and the stool also passes down easily.
  • Increases pressure inside the colon: The rhein anthrones increase the secretion of electrolytes into the colon. They also prevent the absorption of water from the colon. The result? More pressure inside the colon to push the stool out.

Lifestyle Tips

Senna is available as a tablet or syrup, or even as a tea. The ideal dosage is 1 or 2 tablets or spoonfuls (5 ml) at bedtime. The dose for the tea is about 17 mg of the dried herb a day.

Senna takes about 6 to 12 hours to work. So the best time to consume the herb is bedtime. It could cause stomach cramps, diarrhea, and reddish brown urine, but that’ll resolve quickly. That said, don’t consume senna for more than a week at a time. There’s a risk of you becoming dependent on it for regular bowel movement.

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