A selective TRPA1 blocker, antagonizing TRPA1-mediated calcium influx induced by AITC and formalin (IC50 = 6.2 and 5.3 μM, respectively); does not block currents mediated by TRPV1, TRPV3, TRPV4 hERG, or NaV1.2 channels; can be used in cells or delivered to animals orally, by inhalation, or by injection.