What to Mix MiraLAX With
Mix MiraLAX (polyethylene glycol 3350) with any beverage of your choice, though a sports drink containing electrolytes (like Gatorade) is specifically recommended when using it for bowel preparation rather than routine constipation treatment.
For Routine Constipation Treatment
According to the FDA-approved labeling, MiraLAX powder "dissolves in ANY beverage" 1. This gives you complete flexibility:
- Water (most common)
- Juice (apple, orange, cranberry)
- Coffee or tea
- Milk
- Soda (though carbonation may cause bloating)
- Any other liquid of choice
The powder is unflavored and grit-free, making it easy to incorporate into whatever drink the patient prefers 1. This flexibility is particularly valuable in pediatric populations, where studies have shown that allowing children to mix PEG in the beverage of their choice significantly improves compliance 2.
For Bowel Preparation (Off-Label Use)
When using MiraLAX for colonoscopy preparation, you must mix it with a sports drink containing electrolytes—not plain water or other beverages. This is a critical safety distinction 3.
Why Sports Drinks Are Required for Bowel Prep
The 2025 US Multi-Society Task Force guidelines explicitly state: "it is important to mix a sports drink with the PEG-3350 because this bowel purgative is iso-osmotic but not isotonic" 3.
- PEG-3350 alone lacks the electrolytes (sodium, potassium, chloride) needed to maintain isotonicity
- Using plain water or non-electrolyte beverages can lead to electrolyte disturbances during the large-volume purge required for colonoscopy
- Sports drinks like Gatorade provide the necessary electrolytes to maintain safety during bowel cleansing
Common Bowel Prep Protocol
The typical regimen combines:
- 238-459 grams of PEG-3350 (MiraLAX)
- 64 ounces of sports drink (Gatorade)
- Often with bisacodyl tablets 4, 5
Important Caveats
Note that MiraLAX is FDA-approved only for occasional constipation, not for bowel preparation 3. The bowel prep use is off-label, though widely practiced. Recent evidence suggests this off-label regimen may actually produce inferior bowel preparation compared to FDA-approved colonoscopy prep solutions 6.
For standard constipation management at the FDA-approved dose of 17 grams daily, any beverage works fine and electrolyte supplementation is unnecessary 7, 8.