The isolation from commercial Veratrum viride of the five hypotensive ester alkaloids isogermidine, germbudine, neogermbudine, desacetylneoprotoveratrine and veratetrine (neoprotoveratrine) is described. Isogermidine is the diester germine monoacetate-mono-α-methylbutyrate. Germbudine is a diester of the alkamine germine which gives on hydrolysis germine, α-methylbutyric acid and the high melting diastereoisomer of α,β-dihydroxy-α-methylbutyric acid (m.p. 99-100°). Neogermbudine is a new diester of germine in which the esterifying groups are α-methylbutyric acid and the low-melting diastereoisomer of α,β-dihydroxy-α-methylbutyric acid. Desacetylneoprotoveratrine is a known triester of protoverine which gives on hydrolysis one mole each of acetic acid, α-methylbutyric acid and the high melting isomer of α,β-dihydroxy-α-methylbutyric acid. Veratetrine has been shown to be a tetraester of protoverine in which the esterifying acids are two moles of acetic acid and one mole each of α-methylbutyric acid and the high melting α,β-dihydroxy-α-methylbutyric acid. It has been shown to be identical to the alkaloid neoprotoveratrine. The structures of the naturally occurring high and low melting isomeric α,β-dihydroxy-α-methylbutyric acids obtained by hydrolysis of some of these ester alkaloids have been confirmed by the synthesis of the racemic form of the former and both the racemic and resolved optical isomers of the latter, from hydroxylation of tiglic acid. The infrared absorption spectra of these hypotensive alkaloids are recorded for identification purposes.