We have undertaken a comparative pharmacological profile of novel bradykinin antagonists on human B1 and B2 receptor binding and functional assays. We found that there was an excellent correlation between binding and functional data for the compounds at the B1 receptor. In general, although there was a good correlation between the binding and functional data at the B2 receptor there was a greater degree of scatter in the correlation, particularly with compounds that possessed both B1 and B2 binding and antagonist activity. Of the compounds that were highly selective for the B2 receptor, CP-0597 had high binding activity but showed an unexpectedly low functional potency in the human ileum. The reason for this discrepancy is unclear. In general we found that binding activity with both the B1 and B2 antagonist compounds correlated well with their functional activity.