HISTAMINE, slow reacting substance in anaphylaxis (SRS-A) and prostaglandin F2α (PGF2α) are among substances obtained from lungs that contract human isolated bronchial muscle^{1â 4}. Fenamates antagonize bronchoconstriction induced by SRS-A but not that induced by histamine, and they lessen anaphylactic bronchoconstriction in the guinea-pig in vivo^{5â 7}. In view of the possibility, arising from these observations, that fenamates might be useful clinically against pathological bronchoconstriction, we explored how far meclofenamate (sodium N-(2,6-dichloro-m-tolyl) anthranilate)⁸ and flufenamate (sodium N-(α,α,α-trifluoro-m-toryl) anthranilate)⁹ antagonized the contraction of human isolated bronchial muscle induced by histamine, SRS-A or PGF2α.