The gas-liquid chromatography of tertiary Strychnos alkaloids is described. Examination of the alkaloids from S. nux-vomica L. has shown that the method can be readily used for the detection and estimation of strychnine in brucine and vice versa; a new minor base, icajine, has been detected and isolated. Alkaloids from S. icaja Baill. have also been examined. Jaminet's alkaloid A from this plant has been shown to be a mixture of vormicine and icajine. Relationships between the relative retention times and chemical structures are discussed. © 1968.