We studied the influence of Hoe 140, a bradykinin antagonist, on inflammatory reactions induced in rats. Hoe 140 reduced paw oedema induced by bradykinin alone, bradykinin plus prostaglandin (PG) E1, carrageenan, urate crystals or urate crystals plus captopril. The inhibitory effect of Hoe 140 lasted for at least 4 h. Hoe 140 also reduced plasma exudation in sponges implanted in the back of the rat. However it did not modify paw oedema induced by zymosan or by heating the paw at 55 degrees C for 30 s. Carrageenan oedema developed to a small extent in kininogen-deficient rats while the swelling induced by heating the paw of kininogen-deficient rats was the same as that measured in normal animals. Hoe 140 had no effect on the slight swelling induced by carrageenan in kininogen-deficient rats. We conclude that the kinin system is involved in inflammatory reactions induced by carrageenan, urate crystals, sponge implantation but not by zymosan and scalding.