The "Bulgarian treatment" of postencephalitic parkinsonism was originated in 1926 by the Bulgarian plant collector Ivan Raeff. In a previous publication1 it was pointed out that the only effective component of this medication is the Bulgarian belladonna root.
Belladonna roots have rarely been used for therapy. Atropine, hyoscyamine, scopolamine and other alkaloids of this group are usually extracted from the leaves of Atropa belladonna, Hyoscyamus niger, Datura stramonium, Scopolia atropoides or Duboisia myoporoides. In general, these alkaloids are found in roots and leaves, but in different concentrations and in different proportions of the individual alkaloids.Belladonna roots themselves show considerable variation in the concentration and distribution of the alkaloids, the variations depending on the age of the plant, the time of harvest, the geographic location, the climatic condition, the degree of cultivation and storage. For example, Raeff's original Bulgarian root contains 0.86 per cent of total alkaloids
VOLLMER H. "BULGARIAN TREATMENT" OF PARKINSON'S DISEASEPHARMACOLOGIC ASPECTS AND CLINICAL EFFECTS OF ALKALOIDS OF BELLADONNA ROOT. Arch NeurPsych. 1940;43(6):1057-1080. doi:10.1001/archneurpsyc.1940.02280060002001