Description

Evergreen tree growing to a height of 49 ft (15 m). Has large oval leaves and pink streaked yellow flowers on long spikes. Its greenish-grey “fruit” or “apple” is in fact a thickened stem. The true fruit hangs just below this stem and contains the nut, which is encased in red or yellow flesh.

Habitat & Cultivation

This tree is native to tropical American forests and grasslands. It is now cultivated for its highly prized nuts throughout the tropics, especially in India and eastern Africa.

Parts Used

Nuts, leaves, bark, root, gum.

Constituents

The gum contains anacardic acid, which is bactericidal and fungicidal, and kills worms and protozoa.

History & Folklore

The “apple” is made into jams, and, in Brazil, into a liquor called cajuado. The gum exuded by the stem wards off ants and other insects.

Medicinal Actions & Uses

Though many parts of the plant are used medicinally, cashew nut is chiefly a food—after removal of its toxic lining. The nut is highly nutritious, containing 45% fat and 20% protein. The leaves are used in Indian and African herbal medicine for toothache and gum problems, and in West Africa for malaria. The bark is used in Ayurvedic medicine to detoxify snake bite. The roots are purgative. The gum is applied externally for skin conditions such as corns and fungal infection. The oil between the outer and inner shells of the nut is caustic and causes an inflammatory reaction even in small doses. In folk medicine in the tropics, the oil is used very sparingly to eliminate warts, corns, ringworm, and ulcers.

Research

Research at the University of Berkeley (California) has shown anacardic acids to have significant antibacterial activity against Heliobacter pylori, the bacterium thought to be the main cause of stomach ulcers.

Caution

The shell oil and its vapor are highly irritant—do not use in any form.