Use MiraLax powder for oral solution as directed by your doctor. Check the label on the medicine for exact dosing instructions. Use the measuring cap that comes with MiraLax powder for oral solution to measure your dose. Mix the medicine in 4 to 8 oz (120 to 240 mL) of liquid unless your doctor tells you otherwise. You may mix MiraLax powder for oral solution in water, juice, soda, coffee, or tea. Do not use MiraLax powder for oral solution for more than 1 week unless directed to do so by your doctor.