A Fourier transform infrared (FT-IR) spectroscopic method for measuring norditerpenoid alkaloids in larkspurs was developed. Alkaloids were isolated from dry plant material using a simplified extraction procedure and quantitated using FT-IR. Calibration of the method was made from selected larkspur samples with known alkaloid levels determined by high pressure liquid chromatography and gravimetric methods. Thirty-nine samples from three different larkspur species (Delphinium barbeyi D. glaucescens, and D. occidentale) were analysed to demonstrate the ability of the FT-IR method to measure toxic and total alkaloid concentrations in these plants.