In preparation for a colonoscopy, take Fleet Phospho-soda in two doses, as stated by Cornell University. At 5 p.m. on the day before the procedure, drink 1.5 ounces of Fleet Phospho-soda mixed with 8 ounces of water. Follow this by drinking another cup of water or clear liquid.
At 6 p.m., take the identical ratio of Fleet Phospho-soda and water, as directed by Cornell University. Drink at least four to six more glasses of clear liquid before midnight. Examples of clear liquids are fruit juice, clear broth, tea or coffee without creamer, Gatorade and soda. Plain gelatin and ice pops also fit into this category. Stay near bathroom facilities because the laxative effects of Fleet Phospho-soda sometimes appear suddenly and strongly.
Do not consume aspirin or similar drugs -- including ibuprofen and naproxen, arthritis medications or blood thinners the week before the procedure unless otherwise directed by a physician, as cautioned by Cornell University. Do not eat seeds or nuts either.
The day before a colonoscopy, do not consume any solid food or milk products, as advised by Cornell University. Clear liquids are allowed. Most prescription medications taken with sips of water are exceptions; however, diabetes drugs are off limits.