Mix the liquid (not the syrup) with 4 ounces (120 milliliters) of milk, fruit juice, or formula to mask its bitter taste. One to three days of regular use usually are needed for this medicine to take effect. Do not take stool softeners for more than 1 week unless your doctor directs you to. If sudden changes in bowel habits last longer than 2 weeks or if your stools are still hard after you have taken this medicine for 1 week, call your doctor. tell your doctor and pharmacist if you are allergic to any drugs.