Veratrum alkaloids, when treated with concentrated sulfuric acid, or “sulfuric acid reagents” give red, purple, yellow, or violet with characteristic absorption maxima. This reaction can be used as the basis of a simple, rapid colorimetric method for the determination of isolated samples of this class of alkaloids. The final concentration of sulfuric acid is very critical for maximum color development and, since color intensity is decreased if water is present to the extent of greater than 1 per cent, an anhydrous medium is recommended for maximum development. The typical color is best obtained when ethyl alcohol or methyl alcohol is used as the solvent for the alkaloids. Except for hydrochloric acid, no color is obtained with acids other than sulfuric. After heating for several minutes in hydrochloric acid, some color developed, but the intensity was always much less than that produced after treatment of the same amount of alkaloid with sulfuric acid. Inorganic salts, sodium benzoate, and glucose, above certain limiting concentrations, will interfere with color development. Veratrum alkaloids, when treated with concentrated sulfuric acid, or “sulfuric acid reagents” give red, purple, yellow, or violet with characteristic absorption maxima. This reaction can be used as the basis of a simple, rapid colorimetric method for the determination of isolated samples of this class of alkaloids. The final concentration of sulfuric acid is very critical for maximum color development and, since color intensity is decreased if water is present to the extent of greater than 1 per cent, an anhydrous medium is recommended for maximum development. The typical color is best obtained when ethyl alcohol or methyl alcohol is used as the solvent for the alkaloids. Except for hydrochloric acid, no color is obtained with acids other than sulfuric. After heating for several minutes in hydrochloric acid, some color developed, but the intensity was always much less than that produced after treatment of the same amount of alkaloid with sulfuric acid. Inorganic salts, sodium benzoate, and glucose, above certain limiting concentrations, will interfere with color development.