Drink more water. At a minimum, 250 mL (8 oz.) of water should be consumed for every 2.5 grams of PGX taken. Note: PGX Meal Replacement Drink mix contains 4 – 5 g of PGX and PGX SatisFastTM drink mix contains 2.5 g of PGX. A natural laxative such as bran or other insoluble fiber added to the diet may also help. If constipation persists for 3 or 4 days, it is advisable to seek the advice of a medical professional.