Four ephedrine analogues such as ephedrine, pseudoephedrine, methylephedrine, and methylpseudoephedrine were determined by ¹H-NMR from Ephedra species. In the region of δ 5.0—4.0, the signals of H-1 attached to the same carbon with a hydroxyl, were well separated from each other in CDCl₃. The amount of each alkaloid was calculated by the relative ratio of the intensity of H-1 signal to the known amount of internal standard, 200 μg of anthracene. This method allows rapid determination of the quantity of four ephedrine alkaloids from Ephedra species. The amount of these alkaloids was in the range of 1.0—2.0% of dry weight depending on the plant materials.