The method of drinking electrolyte water (Compound Polyethylene Glycol Electrolyte Bulk) before colonoscopy is slightly different in each hospital. Generally, if you have a colonoscopy in the morning, you should drink Compound Polyethylene Glycol Electrolyte Bulk in the evening before and in the morning of the same day. 1. The day before the examination, have a liquid diet at about 17:00 in the afternoon, and drink 1 packet of Compound Polyethylene Glycol Electrolyte Dispersant + 1000ml of lukewarm boiled water at 20:00 to 22:00 in the evening (mixed together and finished within 30 minutes at a temperature of about 40℃). 2. On the morning of the examination, fast for breakfast, drink 1 sachet of compound polyethylene glycol electrolyte bulk + warm boiled water 1000 ml (mixed together, finished within 30 minutes, temperature about 40 ℃) at 04:00-06:00, and fast for food and water until the end of the examination after 06:00. Different dosage forms of Polyethylene Glycol Electrolyte Bulk have different ratios, commonly 1 packet of Compound Polyethylene Glycol Electrolyte Bulk + 1000ml of lukewarm water is taken together. If you feel unwell after taking Polyethylene Glycol Electrolyte Bulk, inform your doctor in time and let him/her decide whether to stop or change the medication to avoid any adverse effect.