A member of the pea family, Alexandrian senna is native to Egypt and Sudan and is cultivated in the warm regions of the world, particularly India and Somalia. Used for centuries as a tea to treat constipation, Alexandrian senna now is an ingredient in many commercially prepared, over-the-counter laxatives. It has a very strong effect and is generally recommended for use only when other remedies — such as lifestyle and dietary changes, as well as more gentle laxatives — have not been effective.
Common Names: Alexandrian Senna, Indian Senna, Tinnevelly Senna, True Senna
Description: Woody shrub, up to 6 feet tall with spreading branches; slender, opposite leaflets in pairs; yellow flowers followed by pealike seedpods up to 3 inches long; fragrant
Hardiness: To Zone 10
Flowering: Varies depending on where it’s growing
Parts Used: Leaves, fruits, and seedpods
Range/Habitat: Native to Egypt and Sudan; cultivated in India and other warm regions
Alexandrian senna has a long history of use as a laxative in both Eastern and Western herbalism. Arab physicians first wrote of the herb’s bowel-stimulating effects in the 9th century, but it was probably used for centuries before that. The herb contains compounds called anthraquinones, which stimulate the colon. Most modern commercial products are made from the plant’s leaflets or fruits, but some authorities say products made from the seedpods have a more gentle laxative effect than those made from the leaves.
When digested, the herb provokes intestinal muscle contractions (peristalsis), thereby speeding the body’s elimination of waste. It’s often taken with carminative (gas-dispelling) herbs, such as ginger (Zingiber officinale), both to reduce intestinal cramping and to mask senna’s bitter and unpleasant — even nauseating — taste. This plant has been well studied in clinical settings.
Caution: Alexandrian senna may cause intestinal discomfort and cramping. To reduce the risk of laxative dependency, the herb should not be used for more than 1 week unless directed by a health-care provider. It should not be taken by women who are pregnant or nursing, by children younger than 10 years old, or by anyone suffering from chronic gastrointestinal conditions, such as colitis or ulcers.
How to grow it
Alexandrian senna grows in moist but well-drained soil in full sun. In Zone 9 and colder, grow this herb in a large container and move the plant indoors when temperatures drop below 45°F. Plant seeds in spring, when temperatures have warmed. Harvest the leaves in summer and the pods in autumn. Propagate the herb from seed or take cuttings in early summer.