For the first time a non-invasive method was employed to record pain-related electrical potentials from the human respiratory nasal mucosa. Gaseous stimulants at painful concentrations were presented by the newly developed stimulating device. The amplitudes of the potentials were found correlated (a) with concentrations of the stimulants, and (b) with subjective estimations of pain intensity. The local anesthetic tetracaine hydrochloride, and also a systemically administered analgesic drug pentazocine given prior to painful stimulation decreased the amplitude of the negative potentials. The peripheral response was interpreted as a summated receptor potential from chemical nociceptors. It is thought to be analogous to the electro-olfactogram. This non-invasive technique of stimulation and recording offers an objective and quantitative measure related to pain sensations and their inhibition by analgesic drugs.