The object of this investigation was the isolation of the individual alkaloids in the hope that the substance or substances responsible for the beneficial effects of Bulgarian belladonna root in certain nervous diseases might be identified. The alkaloids found have been l-hyoscyamine, l-hyoscine, tropine, and bellaradine. The last-named, which has not been found previously, is here described for the first time, has the formula C7H13ON and is very soluble in water. It is a tertiary base containing a reduced pyrrole nucleus. Though our results have been obtained with a Bulgarian sample of belladonna, there is no reason to suppose that tropine and bellaradine would not be found in other samples of the root of any origin. There is no ground for a suggestion that either of these substances plays any part in the beneficial action of the drug in Parkinsonism, and their presence gives no support to the suggested superiority of the Bulgarian drug for this treatment.