The San Bushmen of the Kalahari, one of the world's oldest and most primitive tribes, had been eating the Hoodia for thousands of years, to stave off hunger during long hunting trips.
When South African scientists were routinely testing it, they discovered the plant contained a previously unknown molecule, which has since been christened P 57.
According to the British Heart Foundation 17% of men and 21% of women are obese, while 46% of men and 32% of women are overweight.
So the drug's marketing potential speaks for itself.
Phytopharm's Dr Richard Dixey explained how P.57 actually works:
"There is a part of your brain, the hypothalamus. Within that mid-brain there are nerve cells that sense glucose sugar.
"When you eat, blood sugar goes up because of the food, these cells start firing and now you are full.
