Abstract In 1924, the Therapeutic Research Committee of the American Medical Association appointed a special committee to investigate deaths following the administration of local anesthetics. The Committee for the Study of Toxic Effects of Local Anesthetics found procaine, although a safer clinical alternative to cocaine, was capable of causing death when large doses were injected into tissues and advised that it should be used with caution. This article describes a collaboration beginning in 1928 between Dr John Lundy of the Mayo Clinic and Dr Robert Isenberger of the University of Kansas, which arose from a controversy surrounding systemic adverse reactions to procaine. Isenberger then traveled to the Mayo Clinic to conduct research on various procaine local and spinal anesthesia doses and sodium amytal's protective effect against procaine-induced toxicity. Lundy and Isenberger's work would add to the ongoing discovery of systemic reactions to local anesthetics.