Senna - Cassia spp. (in the Fabaceae or Legume family)
Part used: Leaves.
Taste/smell: Bitter, and slightly sweet.
Dosage: Decoction: 1 heaping teaspoon per cup of water; or 1:5 dry liquid extract: 20 - 60 drops 1-4 times per day in a little water.
Mental picture and specific indications: Senna is indicated for constipation with lack of muscular action, flatulence, colic and enlarged, tender liver.
Use: (a) Laxative, (b) Cholagogue.
Senna acts on the large intestine to stimulate peristalsis and increase secretion of water into the large intestinal lumen. It is used in constipation, anal fissures, hemorrhoids and after rectal operations. All uses are due to the laxative effect and it is specific for chronic constipation. The constituents in this herb are activated by intestinal flora. The constituent, emodin, has been shown to possess anticancer, antibacterial, diuretic, immunosuppressive and vasorelaxant activities in research with animals.
Contraindications: Do not use for extended periods of time. Chronic use will deplete electrolytes, especially potassium, bringing about muscle weakness and increased constipation. Potassium loss can disturb cardiac rhythm and potentiate cardiac glycoside toxicity as found with digitalis use. Individuals who consume formulas with anthraquinones, while taking cardiac glycosides, should have their medication monitored by their physician to make sure they do not receive a toxic dosage of cardiac glycosides. Herbs with cardiac glycosides include pheasant's eye (Adonis) lily of the valley (Convallaria), fox glove (Digitalis), false hellebore (Helleborus), Strophanthus and Urginea.
Potassium depletion can lead to paralysis of intestinal musculature that makes the laxative less effective. More of the laxative needs to be taken for the same effect. Eventually, the person may end up with rebound constipation.
An overdose or overusage of anthraquinones may cause vomiting, intestinal spasms and bloody diarrhea. No anthraquinone-containing herbs should be consumed by pregnant women or nursing mothers. These herbs should also not be taken by individuals with damaged kidneys or kidney inflammation. Large doses may cause nephritis. Senna is contraindicated for children under age 12 due to loss of water and electrolytes and in abdominal pain of unknown origin. Emodin has also been reported to be a mutagen in a few experiments.