Abstract: A method for extracting benzo-c-phenanthridine alkaloids from plants of the families Papaveracease Fumariaciae, and Berberidacae, comprising extracting ground plant material with acidulated methanol precipitating the extract with an acid salt which is soluble in methanol, redissolving the precipitated salt in water, adding sufficient acid to form a precipitate, and collecting the precipitate so formed. The benzo-c-phenanthridine alkaloids have valuable properties as antimicrobials as well as in treating mouth odors, gingivitis, and periodontitis.