MiraLAX (polyethylene glycol 3350) typically works to produce a bowel movement within 1 to 3 days after taking it
. More specifically, it usually takes about 12 to 24 hours to start working, but in some cases, it can take up to 96 hours (4 days)
. MiraLAX works by drawing water into the colon, which softens the stool and increases its volume, making it easier to pass without causing sudden urgency or harsh side effects
. Unlike stimulant laxatives, it does not directly stimulate intestinal contractions, so the onset is more gradual. Factors that influence how quickly MiraLAX works include:
- Dosage taken (standard dose for constipation is 17 grams dissolved in 4-8 ounces of liquid)
- Severity and cause of constipation (severe or chronic constipation may delay effects)
- Individual digestion speed and existing gastrointestinal conditions
- Staying well hydrated can help MiraLAX work more effectively
For colonoscopy bowel preparation, a larger dose of MiraLAX is used, which typically produces bowel movements within a few hours
. In summary, expect MiraLAX to work within 1 to 3 days for occasional constipation, with some variability depending on individual factors. If no bowel movement occurs after 7 days of use, or if constipation worsens, medical advice should be sought
