Mefloquine was one of around 250,000 chemical compounds tested for malaria-killing activity in the 1960s by the United States military who needed to protect troops from malaria in the tropics.
The flowering tops and aerial parts of the St John's Wort plant are used medicinally in the form of tinctures and tablets to treat a number of conditions affecting the nervous and immune systems.
Ibuprofen can be obtained easily from supermarkets without consulting a health care professional. While this may make it seem it's benign, it can have ill effects if used inappropriately.
Ecstasy is the street name for 3,4-methylenedioxymethamphetamine, or MDMA, an illicit party drug that speeds up messages to and from the brain and alters the user's perception of reality.
The US National Cancer Institute screened 35,000 plants, but one particular sample collected from the bark of the Pacific Yew tree provided what is now one of the most highly prescribed cancer drugs.
Warfarin is a blood thinner that has been used for more than 60 years to help prevent clots and strokes. But it also increases the risk of bleeding.
Lipitor was approved by the government in 1997, and while under patent protection it was the highest-selling drug of all time with worldwide sales of more than US$12 billion a year.