The invention relates to alkaloid reaction products obtainable in a process wherein alkaloids are reacted with an alkylating agent, preferably thiotepa, whereafter unreacted alkylating agent and other water-soluble compounds are removed from the reaction mixture by washing with water or a suitable aqueous solvent, whereafter the reaction mixture is subjected to a treatment with strong acid, preferably hydrogen chloride (HCl), to precipitate a water soluble salt of the reaction products. The precipitated reaction products comprise at least one quaternary alkaloid derivative and are suitable as drugs for prophylactic or therapeutic application, particularly in the treatment of immunological or metabolic dysfunctions, and cancer. <;IMAGE>;