Senna includes herbs, shrubs, and trees. The leaves are pinnate with opposite paired leaflets. The inflorescences are racemes at the ends of branches or emerging from the leaf axils.
The caterpillars of many Lepidoptera species feed on Senna plants.
Senna species are pollinated by a variety of bees, especially large female bees in genera such as Xylocopa.
Some species also have extrafloral nectaries on the leaves or flower stalks, which attract ants, but do not benefit pollinators.
The inflorescences are racemes at the ends of branches or emerging from the leaf axils.
Sennas have for millennia played a major role in herbalism and folk medicine.
The glycosides increase gastric fluid secretion and bowel motility, producing laxative action.
Senna preparations are available in powders, granules, tablets, oral infusions, and syrups.
Several Senna species are used as herbal remedies in Nigeria to treat various conditions, including constipation, fungal skin infections, and hemorrhoids.