A new method of administering d-tubocurarine transmucosally by sublingual pellets (and also by rectal suppository) was used in 100 patients. In therapeutic dosage of 6 to 12 mg., it was found to be non-toxic and very effective in relieving pain due to acute and chronic muscle spasm. The relief was often of long duration or permanent and no unpleasant side effects were noted in any case. The drug was found to be more prompt and more effective in its action than mephenesin. In addition to relief of pain, it was found to be useful in distinguishing between kinds of pain and hence in differential diagnosis.