bowel preparation
"It was $80 co-pay but worked well for me with only five 8-oz cups of water in the evening and three in the morning.  I wouldn't be able to drink a gallon of alternative medication with gastritis. 
Important to follow instructions and mix the powder with water for at least 2-3 minutes, otherwise you will have nausea. It becomes warm when mixed.  Set multiple alarms/look at the clock to drink water in recommend intervals.  You will likely get an irritation of your butt from flushing out.  Be prepared with Vaseline/A&D ointment and warm water baths to relieve the symptoms.  I scheduled the appointment for 12:30 pm which was the latest available to avoid getting up at night as you need a few hours for your morning doze to finish working."