Epidemiological studies have found that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs) is associated with a lower risk of colorectal cancer (CRC). Cyclooxygenase (COX)-2 expression is present in colorectal cancer and overexpression is associated with metastases and poorer prognosis in multivariate analysis. NSAID treatment results in a reduction of the incidence of colorectal adenoma in patients with familial adenomatous polyposis, in patients with a history of colorectal adenomas and in patients with a history of CRC. Pre-clinical research shows that COX-2 expression is associated with cell proliferation, angiogenesis, apoptosis inhibition and local immune-down modulation. An anticarcinogenic effect has been shown specifically in selective COX-2 inhibitors in animal models. Selective COX-2 inhibitors have fewer adverse effects than the non-selective NSAIDs and are promising chemopreventative and chemotherapeutical agents. The effects of selective COX-2 inhibition in the prevention of and treatment for colorectal carcinoma will be investigated in clinical randomized multicentre trials.