 We propose to test the hypothesis that celecoxib, a specific inhibitor of cyclooxygenase -2 COX-2, will effectively inhibit the enzymatic activity in all tissues sampled after oral administration of celecoxib for 7 days preoperatively. One hundred twenty patients 120 undergoing standard surgical resection for the treatment of primary colorectal adenomas or carcinomas would be randomized to celecoxib or placebo given for 7 days prior to operation. Peripheral blood will be drawn prior to drug or placebo administration, and then morning of operation. At the time of definitive resection of the specimen, normal intestinal mucosa and primary tumor would be harvested and immediately snap frozen at -80 degrees. Levels of COX-2 activity prostaglandin production as well as expression of COX-2 and other markers matrix metalloproteinasesMMPs, tissue inhibitors of MMPs TIMPs, cell adhesion and cell cycle control molecules will be evaluated in normal mucosa and primary tumor compared between celecoxib and placebo treated patients. 