Ephedra is a medicinal preparation from the plant Ephedra sinica. Known in Chinese as ma huang (; pinyin: má huáng, which literally translates into English as "Yellow Hemp"), it has been used in traditional Chinese medicine for 5,000 years.Several additional species belonging to the genus ephedra have traditionally been used for a variety of medicinal purposes, and are a possible candidate for the Soma plant of Indo-Iranian religion.Native Americans and Mormon pioneers drank a tea brewed from other ephedra species, called "Mormon tea" and "Indian tea".

A wide variety alkaloid and non-alkaloid compounds have been identified in various species of ephedra. Of the six ephedrine-type ingredients found in ephedra (at concentrations of 0.02-3.4%), the most common are ephedrine and pseudoephedrine. The stimulant and thermogenic effects of Ephedra sinica and other ephedra species are due to the presence of the alkaloids ephedrine and pseudoephedrine. These compounds stimulate the brain, increase heart rate, constrict blood vessels (increasing blood pressure), and expand bronchial tubes (making breathing easier). Their thermogenic properties cause an increase in metabolism, as evidenced by an increase in body heat.

Ephedra has been used as a weight-loss aid, sometimes in combination with aspirin and caffeine. Some studies in regulated and supervised environments have shown that ephedra is effective for marginal short-term weight loss (0.9 kg/month more than the placebo)