The Kalahari Desert is a harsh desert, but biologically a very active one. South Africa, Angola, Namibia and Botswana border the desert. The native tribe, known as San or Bushman by the white South Africans, is one of the oldest living tribes in the world, may be as old as 100,000 years. Even then, they do not live a settled life with agriculture or animals rearing. They are pure hunter-gatherers. They were hunted down by the white settlers of South Africa as a nuisance, and as late as the early part of 20th century, there were hunting parties organized to exterminate them.

When the San go on long hunting trips following the game, they eat a cactus-like plant and they do not feel hunger or thirst for a long period. They called it Xhoba. South Africas government research organization, CSIR (Council of Scientific and Industrial Research), in a routine investigation tested this plant and found that this indeed blocked the sense of hunger and gave a feeling of fullness to the stomach.

Hoodia is the name of the plant, and it is not a cactus but a succulent in the family of Asclepiadaceae. It is multi-stemmed (about 18 inches high, averaging ten tentacles), looks like a long cucumber with spikes, smells unpleasant, and has purple disc-shaped flowers of three to four inches in diameter. It is bitter tasting and grayish brown in color.

CSIR scientists isolated the active ingredient, which gave the feelings of fullness when consumed. It is a molecule that they named P 57. There are about twenty varieties of Hoodia, but only one of them is Xhoba, with the ingredient P 57. This is Hoodia Gordoni. In 1776 Col. R. J. Gordon, while exploring the Orange River, found this plant and recorded it. It is named after him as Hoodia Gordoni. It is also called Queen of Namibia and African hats.

Medication made from this plant is one of the hottest products in the market for weight-reducing treatments.