Diethazine is the antimuscarinic agent. It has actions similar to those of ethopropazine but it is more toxic. Diethazine is used for the palliative treatment of the parkinsonian syndrome. It is more useful in the treatment of Parkinson’s disease than in allergies. Blockade of single contractions observed in these experiments after administration of diethazine was independent of the frequency of stimulation of the nerve. This suggests that the drug acts directly on the postsynaptic receptor in the endplate.