Anaphylaxis occurs in 1/5000–1/20,000 of anesthesia cases and may evolve with shock and cardiovascular collapse in up to 54% of cases. Mortality varies from 3% to 10%. Latex is the second leading cause of anaphylaxis during the perioperative period. We report a case of latex-induced anaphylactic shock refractory to the usual catecholamine treatment that was reversed with the aid of methylene blue. Exaggerated activation of the nitric oxide–cyclic guanosine monophosphate pathway is observed in refractory shock. Methylene blue selectively inhibits this pathway.