An alkaloid, C6H5CH(OH)CH(CH3)NHCH3 found in plants of the genus Ephedra, once used as a bronchodilator in the treatment of asthma. It is also used as a stimulant and appetite suppressant. Structurally, it is a phenylethylamine and is similar to amphetamines, although less active. It is, however, widely used in the illegal synthesis of methamphetamine. The molecule has two chiral centres. If the stereochemical conformations are opposite (i.e. 1R,2S or 1S,1R) the name ephedrine is used. If the conformations are the same (1R,2R or 1S,2S) then the compound is called pseudoephedrine.