Inhibitors of the inducible cyclooxygenase (COX-2) have emerged as a promising new class of drugs that may be useful for the prevention of colorectal cancer. Experimental evidence to support such a claim has come from both clinical and laboratory findings that show that both selective and nonselective COX inhibitors effectively block tumor growth. Although the precise mechanism(s) by which these drugs modulate tumor growth is not known, there is evidence from colon carcinoma cell culture studies that COX-2 activity may play an important role in regulating angiogenesis and apoptosis. Recent data obtained in animal studies suggest that COX-2 inhibitors may also be useful in the treatment of established colorectal tumors. Treatment of COX-2 expressing tumor cells with selective COX-2 inhibitors appears to reset the balance between cell proliferation and cell death such that there is no increase in tumor volume.