We have examined the cannabinoid contents of seedlings from twelve strains of Cannabis of known chemical race. Fourteen days after emergence of the shoot those of the tetrahydrocannabinol (THC) type could be distinguished from those of the cannabidiol (CBD) type. The true leaves of the THC type contained a relatively high content of THC and also contained cannabichromene (CBC), sometimes as the major cannabinoid, whereas the CBD type had much lower amounts of THC and no CBC; CBD being the major component. A strain from China corresponded to the THC type but showed some unusual features. Seeds purchased at seven outlets in Britain were also examined. Only two batches germinated by these proved to be of a THC type and resembled the Chinese strain.