Standard Adult Dosage for Constipation

The typical over-the-counter dosage of polyethylene glycol 3350 for adults is:

Powder form:

One heaping tablespoon (17 grams) once daily
Mix in 4-8 ounces of water, juice, coffee, or other beverage
Stir until completely dissolved
Drink immediately or can be refrigerated

Pre-measured packets:

One packet (17 grams) once daily
Mix according to package directions
Typically 4-8 ounces of liquid

The medication is taken once daily, making it very convenient.

How to Take Polyethylene Glycol

Proper mixing:

Pour the recommended liquid (4-8 ounces) into a glass
Add one dose of polyethylene glycol powder
Stir until completely dissolved (usually 2-3 minutes)
Drink the entire mixture

Important notes:

Polyethylene glycol dissolves completely (no grit or texture)
Mixture is tasteless or nearly tasteless
Can be mixed with any beverage (water, juice, coffee, soda, etc.)
Some people prefer cold beverages
Can prepare and refrigerate for later use (within 24-48 hours)

Liquid Volume

The amount of liquid used for mixing:

Minimum: 4 ounces
Maximum: 8 ounces
More liquid makes it easier to drink but is not required for effectiveness
Less liquid makes the dose smaller but more concentrated
Works the same regardless of liquid volume used

Choose the volume that is most comfortable for you.

Children’s Dosing

For children and adolescents:

Children 17 years and older:

Adult dose (17 grams daily)

Children under 17 years:

Should only use under healthcare provider direction
Dosing is often weight-based for younger children
Many pediatricians recommend it for childhood constipation
Not for self-treatment in young children

Polyethylene glycol is frequently prescribed for children but should be used under medical supervision in pediatric populations.

When to Take Polyethylene Glycol

Time of day:

Can be taken at any time
Many people prefer morning or before bed
Consistency helps establish regular bowel patterns

With meals:

Can be taken with or without food
No dietary restrictions
Some people prefer taking it before breakfast

Timing for results:

Works best when taken daily at the same time
Produces bowel movements at variable times (usually within 24-72 hours initially)
With regular use, patterns become more predictable

Duration of Use

Unlike many laxatives, polyethylene glycol can be used long-term:

For occasional constipation:

Use daily until constipation resolves
Typically 1-2 weeks
Can stop when regular bowel movements return

For chronic constipation:

Safe for daily use indefinitely
Many people use it as part of their permanent routine
Does not cause dependency
No maximum duration

If using daily for more than 2 weeks for the first time, consider consulting a healthcare provider to evaluate underlying causes.

Maximum Daily Dosage

For over-the-counter use:

Standard dose: 17 grams (one dose) per day
Do not exceed this amount without medical supervision

Prescription use:

Healthcare providers may recommend higher doses for resistant constipation
Can be increased to 34 grams (two doses) daily in some cases
Should only exceed standard dosing under medical direction

Adjusting Dosage

Finding the right dose and frequency:

If one daily dose is not sufficient:

Ensure you are taking it every day consistently
Give it adequate time (several days to a week)
Drink plenty of water throughout the day
Consult healthcare provider before increasing dose

If one daily dose causes loose stools:

Reduce to every other day
Or reduce to half dose daily
Adjust to find your optimal dose

Some people find they need it daily, while others achieve good results with every-other-day dosing.

Missed Dose

If you miss a dose:

Take it when you remember
If it is close to the next scheduled dose, skip the missed dose
Do not double up to make up for a missed dose
Resume regular schedule
Consistency improves effectiveness

Forms and Brands

Polyethylene glycol 3350 is available in:

Brand names:

MiraLAX
GlycoLax
ClearLax
Many others

Generic versions:

Widely available and much less expensive
Identical active ingredient and effectiveness
Good option for long-term use

Packaging:

Small containers (7-14 doses)
Large containers (30-45+ doses)
Individual packets for travel

All contain the same active ingredient: polyethylene glycol 3350.

Special Considerations

Kidney Disease

People with kidney disease:

Should consult a healthcare provider before use
May need monitoring of electrolyte levels with long-term use
Generally safe but requires medical oversight

Electrolyte Imbalances

People with existing electrolyte problems:

Should use under medical supervision
May need periodic lab monitoring
Generally well-tolerated but caution advised

Eating Disorders

People with eating disorders:

May misuse laxatives
Should use only under medical supervision
Need comprehensive treatment approach

Older Adults

Older adults can use standard adult doses:

Ensure adequate hydration
Monitor for any adverse effects
Often very helpful for medication-induced constipation
Safe for long-term use

Drug Interactions

Polyethylene glycol has minimal drug interactions:

Does not significantly affect absorption of most medications
Can be taken without timing considerations relative to medications
Much simpler than psyllium regarding drug interactions

However, inform healthcare providers that you use it.

Combining with Other Treatments

Can be combined with:

Dietary changes
Increased water intake
Exercise
Stool softeners (sometimes, under medical guidance)

Generally avoid combining with:

Other osmotic laxatives
Stimulant laxatives (unless specifically directed by healthcare provider)

Consult a healthcare provider before using multiple laxative types together.

What If It Does Not Work?

If polyethylene glycol does not relieve constipation after 7 days of consistent use:

Check these factors:

Are you taking it every single day?
Are you drinking adequate water throughout the day?
Are there medications or conditions contributing to constipation?

If still not working:

Consult a healthcare provider
May need dose adjustment
Underlying causes may need evaluation
Different treatment approach may be needed

Do not:

Exceed recommended doses without medical advice
Continue indefinitely without medical evaluation
Add stimulant laxatives without consulting a provider

Storage and Handling

Store at room temperature
Keep container tightly closed
Keep out of reach of children
Check expiration dates
Can be mixed and refrigerated for 24-48 hours if needed

Measuring Accurately

For powder form:

Use the measuring cap or scoop provided
One heaping tablespoon = 17 grams
Do not use regular kitchen spoons (measurement may be inaccurate)
Level scoops may not provide full dose

Accurate measurement ensures consistent effectiveness.

When to Contact a Healthcare Provider

Consult a healthcare provider if:

Constipation persists after 7 days of daily use
You develop severe abdominal pain
Rectal bleeding occurs
You experience persistent nausea or vomiting
You have kidney disease or electrolyte concerns
You need guidance on long-term use
Symptoms worsen despite treatment

Polyethylene glycol laxatives are widely available over the counter — view on Amazon.

Sources

MedlinePlus. Polyethylene Glycol 3350. https://medlineplus.gov/druginfo/meds/a601002.html. Accessed March 2026.
National Institute of Diabetes and Digestive and Kidney Diseases. Constipation. https://www.niddk.nih.gov/health-information/digestive-diseases/constipation. Accessed March 2026.

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