We shall continue to study the metabolism of various cannabinoids by man, including the excretion of unchanged tetrahydrocannabinol (THC). Our techniques will include both thin layer chromatography and high pressure liquid chromatography. The pharmacokinetics of THC will be examined by measurements of plasma concentrations of the drug and these will be compared with clinical evidence of impairment to define a range of concentration that would be useful forensically. The therapeutic action of THC homologs, such as nabilone, will be studied in patients with vomiting induced by cancer chemotherapy. Interactions between THC and changes in neurotransmitters, for example acetylcholine, will be studied with the idea of gaining insight into the mechanism of action.