【How-to】How miralax works - Howto.org

Basically, osmotic agents, such as polyethylene glycol found in MiraLAX^®, work naturally with the water in the colon to unblock a person’s system. Soluble, non-absorbable PEG 3350 hydrates, softens and eases stools by gently attracting water in the colon through a process known as osmosis.