Preparation for a colonoscopy involves emptying the colon, so this process includes a special diet for 24 hours before the test, as well as a laxative and enema in some cases. Some patients need to adjust their medications as well, states Mayo Clinic.
Patients are not allowed to eat any solid food for 24 hours prior to the examination, and beverages are limited to liquids that are clear, such as carbonated drinks, broth, water, tea and coffee without any dairy products. Patients should avoid red liquids as well, as those can show up as blood during the test. Some patients have a total restriction against any food or beverages starting at midnight the night prior to the colonoscopy, according to the Mayo Clinic.
Some patients require the use of an at-home enema kit to empty the colon the night before the test or several hours before the procedure. Other patients take a liquid or pill laxative the night before, or both the night before and the same morning as the test, as stated by Mayo Clinic.
With some medical conditions, such as diabetes, heart problems, high blood pressure or any condition requiring medications with iron, the doctor may have the patient adjust or stop certain medications for a short time. Aspirin, blood thinners and anticoagulants may also need adjustment before the colonoscopy, notes Mayo Clinic.