Medicinal marijuana advocates contend that smoking pot helps relieve pain and alleviate nausea. British drug company GW Pharmaceuticals is betting that medicine made from cannabis can also treat maladies as diverse as diabetes, colitis, and epilepsy.
GW is the only pharma group in the world now selling a prescription medicine derived from marijuana plants, as opposed to synthetic equivalents. The drug, a mouth spray called Sativex, has been approved by regulators in eight countries—Italy, most recently—to treat spasms associated with multiple sclerosis. A request for U.S. Food and Drug Administration approval is pending.