How much water does a patient drink with laxative the day before colonoscopy?

Typically, a patient is instructed to drink a large volume of water (often around 3-4 liters or 1-2 gallons) along with the laxative preparation the day before a colonoscopy. The exact amount of water recommended may vary depending on individual factors such as weight and medical history, and the specific instructions provided by the doctor or healthcare team should be followed.