Agathosma is a genus of about 140 species of flowering plants in the family Rutaceae, native to the southern part of Africa. Common names include Buchu, Boegoe, Bucco, Bookoo and Diosma. Buchu formally denotes two herbal species, prized for their fragrance and medicinal use. They are small shrubs and subshrubs, mostly with erect woody stems reaching 30cm to 100cm tall, but low-growing and prostrate in some species. Many of the species are highly aromatic, and the genus name means “good fragrance”. Some species of the genus, most notably Agathosma betulina are used as herbal remedies. The buchus grown commercially for their medicinal properties and essential oils are Agathosma crenulata and Agathosma betulina. Oil is extracted for use in manufacturing cosmetics, soaps and medicinally for the treatment of renal disorder and chest complaints. The medicinal properties of these plants were discovered by the Khoi who named the plants “buchu”.

Agathosma betulina, previously known as Barosma betulina, is endemic to the lower elevation mountains of western South Africa, where it occurs near streams in fynbos habitats. Common names include boegoe, bergboegoe, buchu and round leaf buchu. Buchu, originally a highly prized San and Khoi-khoi traditional remedy, has remained one of the most popular herbal medicinal plants in South Africa. Its traditional use encompasses the treatment of kidney and urinary tract infections, colds, stomach ailments, rheumatism, gout and fever. Externally it is applied as an antiseptic wash to infected wounds and as a compress to relieve swelling, bruising and sprains. In traditional practice, Agathosma betulina is most commonly taken orally in the form of an aqueous infusion sometimes sweetened with brown sugar, or as a tincture in brandy. Other dosage forms include a vinegar infusion, for external application as an antiseptic wash or embrocation. The essential oils and extracts of the leaves are used as flavouring for teas, candy, and a liquor known as buchu brandy in South Africa. The extract is said to taste like blackcurrant.