The most disabling form of Parkinsonism is that occurring after encephalitis. It may occur in persons of any age. The results of surgical treatment, which has been used for the most part only for seriously handicapped patients, have been discouraging in general, although in a few isolated circumstances operation has been of dramatic benefit.The solanaceous alkaloids-atropine, stramonium and hyoscine-either in pure forms or in mixed extracts or tinctures - are the best established drugs at present for the treatment of the postencephalitic forms of Parkinsonism. They have not proven too helpful for patients in the older age group with paralysis agitans. The antihistaminic compounds, particularly Benadryl,(R) have been a very valuable addition. They are of greatest value for patients in the older age group. The newer synthetic compounds, Artane(R) and Panparnit,(R) are also valuable additions. Amphetamine and the related and subsequently produced agents in this group are very helpful for patients showing undue fatigue and lethargy. Tolserol(R) is proving helpful, particularly for patients with painful spasms of rigid muscles.