Yohimbe (Pausinystalia yohimbe) is native to the forests of western Africa. The Bantu tribe used its bark as a male aphrodisiac, and the herb has been used in conventional medicine to treat impotence.
Yohimbe contains alkaloids that stimulate the brain, but they are toxic in high doses. The castor bean (Ricinus communis), from which we obtain castor oil, was listed in the Ebers papyrus.
The plant is believed to be native to eastern Africa and is cultivated today in hot climates around the world. The seeds are toxic but oil from the seeds is not. Castor oil is used as a base in cosmetics and as a laxative; recently, researchers have been exploring the castor bean’s effectiveness as a contraceptive.
Aloe (Aloe vera) is native to eastern and southern Africa. Legend has it that Cleopatra attributed her beauty to aloe vera gel, which comes from the leaves. At the base of aloe leaves, one can find a yellow sap that, when dried, yields “bitter aloes,” which are strongly laxative.
Aloe gel is a powerful healer of burns and wounds, and research shows that the gel contains aloectin B, which stimulates the immune system.
Senna (Cassia senna) is native to tropical Africa and was first used medicinally by Arabian physicians in the ninth century. Then, as now, its medicinal value comes from its strength as a laxative. Senna causes the muscles of the large intestine to contract and prevents fluid from being absorbed.