Chemoprevention (using drugs to prevent cancer), cannot be recommended for the general population of healthy individuals.

Any chemoprevention should only be started after first consulting a physician who can supervise the treatment. Self-medication with aspirin or other potential chemopreventive drugs is strongly discouraged, since the use of these drugs may be associated with serious and potentially lethal adverse events.

Although the preventive effect of aspirin against colorectal cancer has been proven, the indications are limited. Aspirin therapy, even at low doses, may be associated with serious adverse events, including upper gastrointestinal bleeding and (more seldom) haemorrhagic stroke. Furthermore, the best dose and duration of aspirin therapy for chemoprevention have not been established. Until these questions have been resolved, the chemopreventive use of aspirin or other NSAIDs should be restricted to patients at high risk of colorectal cancer, including individuals with hereditary conditions and, perhaps, patients with previous colorectal adenomas or cancer.