An investigation of the hypotensive alkaloids of Veratrum album has resulted in the finding that protoveratrine prepared from this source is a mixture of two alkaloids and in the isolation of a new hypotensive alkaloid, named germitetrine B, from the "amorphous alkaloid" fraction. One of the alkaloids, protoveratrine A, was found to conform to the accepted structure of protoveratrine except that it yielded two instead of one mole of acetic acid on hydrolysis. Protoveratrine B was found to yield protoverine, 2-methylbutyric acid, 2,3-dihydroxy-2-methylbutyric acid and two moles of acetic acid on hydrolysis. Germitetrine B was found to yield germine, 2-methylbutyric acid, 2,3-dihydroxy-2-methylbutyric acid and two moles of acetic acid. The original purpose of the work reported here was to prepare protoveratrine for clinical testing and then to search for alkaloids responsible for the hypotensive activity of the so-called "amorphous alkaloid" fraction from Veratrum album. Paper chromatographic methods developed to aid in following the fractionation of the "amorphous alkaloids" soon revealed that protoveratrine, itself, as prepared by the technique of Craig and Jacobs, was, in fact, a mixture of two alkaloids. This necessitated a reinvestigation of the chemistry of protoveratrine. Such mixtures of two alkaloids were encountered in protoveratrine from all six lots of Veratrum album roots and rhizomes examined. The proportion of protoveratrine B varied from 0.36 to 0.58 among these six different lots. No significant variation was noted among different preparations from the same lot. Attempts to separate the two alkaloids by fractional crystallization were unsuccessful. Separation of protoveratrine into protoveratrine A and B on a macro scale was accomplished by a Craig countercurrent distribution procedure using a chloroform-water-acetic acid system. After removal of "protoveratrine" from the total alkaloids, considerable hypotensive activity remained in the residual "amorphous alkaloid" fraction. Application of paper chromatographic methods to the examination of this fraction showed the presence of at least fifteen alkaloids. To isolate individual alkaloids from this fraction, a 19-plate countercurrent distribution was carried out using a methylene chloride-water-acetic acid system. Biological assays showed high hypotensive activity associated with an alkaloid peak in funnels 11-14. Combination of the material recovered from funnels 11-16 and crystallization from butyl chloride gave an alkaloid which after repeated recrystallization from butyl chloride and recrystallization from aqueous acetone melted at 233-234° (slight decomposition on melting) ([α]25D in pyridine -70°). This alkaloid showed hypotensive activity and was named germitetrine B. Protoveratrine A, protoveratrine B and germitetrine B all show hypotensive activity, protoveratrine B being slightly less active than the other two.