In order to prepare for a colonoscopy, the colon must be cleansed so that its inner surface will be visible. Prior to the colonoscopy, patients are given written instructions which may vary a bit from one physician to another. Typically, the patient is told to drink clear liquids for a day or two before the procedure, including water, tea, coffee, strained fruit juices, sports drinks and clear broths. Patients are also permitted to consume gelatin. One strict prohibition is any liquid or gelatin with a red or purple coloration.
The day before the procedure, patients are instructed to drink a quantity of a special laxative solution or to take a large number of laxative pills. It is important that the patient remain close to home during this day because the toilet must be available for frequent use.
Patients who take aspirin or other blood-thinning medication must advise their doctors before going through the colonoscopy procedure. Most other medications can be continued.