"Efocaine," a long-acting local anesthetic, a product of E. Fougera & Co., has been publicized widely and is being used freely by the medical profession. "Efocaine" is a solution containing 1% procaine, 0.25% procaine hydrochloride, and 5% butyl-p-aminobenzoate in a solvent composed of 2% polyethylene glycol-300, 78% propylene glycol, and water. It is preserved with the usual preservatives, 0.1% sodium metabisulfite, and phenylmercuric borate (1:25,000). Bonica1 has recently reported his experience with the use of "efocaine" in 100 patients. In six of these patients, postinjection neuritis and pain were encountered. He does not give details as to the seriousness or duration of disability in these patients. We have recently encountered three cases in which serious neurological residuals have resulted from the use of "efocaine." The purpose of this report is to urge caution in the use of this drug. REPORT OF CASES Case 1.—On Sept. 9, 1952,