miralax powder laxative, 34 doses, 20.4 ounce miralax size: 21.5 oz miralax is the #1 doctor recommended laxative, providing effective and predictable relief for occasional constipation. miralax is clinically proven to relieve occasional constipation and soften stool without causing harsh side effects such as sudden urgency, cramping, bloating and gas. miralax powder dissolves completely in water or any hot or cold beverage of your choice with no added taste or grit. works with the water in your body to hydrate, soften, and ease to unblock your system naturally. use as directed for occasional constipation.