The Maasai of east Africa use a drug called Olkiloriti which is obtained from the preparation of the root and bark of the Mimosa nilotica tree.  It is used as a narcotic, excitant, stimulant, and to prevent hunger and thirst. Warriors use Olkiloriti prior to battle in order to enter a state of frenzy, and to prevent fear & fatigue.
Medicinally, Olkiloriti is used by the Maasai to aid digestion, treat dysentery, tuberculosis and impotence.
In East Africa the bark is used as a stimulant. The root is also used as an aphrodisiac and to treat impotence.
Mimosa nilotica is also a source of antioxidants. Some crude extracts seem to have stronger antioxidant properties than either vitamin C or vitamin E.
Compounds found in the leaves include N,N-dimethyl-tryptamine, and tetrahydroharmane (Bhakuni et al. 1969).