Colace vs MiraLAX: Stool Softener vs Osmotic Laxative

Quick Answer: Colace (docusate sodium) is a stool softener; its label says it generally produces a bowel movement in 12 to 72 hours. MiraLAX (polyethylene glycol 3350, 17 g) is an osmotic laxative that generally works in 1 to 3 days. The 2023 AGA-ACG guideline on chronic idiopathic constipation made a strong recommendation for polyethylene glycol; docusate was not among the recommended agents, and reviews describe its evidence as weak. Both labels say to stop and see a doctor for rectal bleeding or if you need a laxative for more than 1 week.

Colace vs MiraLAX at a Glance

Feature	Colace (docusate sodium)	MiraLAX (PEG 3350)
Type	Stool softener (surfactant)	Osmotic laxative
How it works	Lets water and fat mix into stool	Holds water in the bowel to soften stool and increase frequency
Label onset	12–72 hours	1–3 days
Adult dose (label)	50 mg softgels: 1–6 daily	17 g in 4–8 oz of beverage once daily
Age on OTC label	12+ (children 2–11: 1–3 softgels)	17+ (16 and under: ask a doctor)
AGA-ACG 2023 guideline	Not among recommended agents	Strong recommendation
Label duration limit	Ask a doctor if needed over 1 week	Do not use more than 7 days without a doctor

Doses above are from the current U.S. Drug Facts or prescribing labels listed in Sources. Always follow the label on the package you buy, because store brands and formulations differ.

How They Work

Docusate is a surfactant, a detergent-like compound meant to let water and fats penetrate hard stool and soften it. It does not stimulate the bowel or add bulk. Polyethylene glycol 3350 is a large molecule that is not absorbed; it holds water in the colon, which softens stool and increases the number of bowel movements.

What the Evidence Shows

In 2023, the American Gastroenterological Association and American College of Gastroenterology published a joint guideline on medicines for chronic idiopathic constipation in adults (Chang et al.). The panel made strong recommendations for polyethylene glycol, sodium picosulfate, linaclotide, plecanatide and prucalopride, and conditional recommendations for fiber, lactulose, senna, magnesium oxide and lubiprostone. Docusate was not among the recommended agents.

A 2019 “Things We Do for No Reason” review in the Journal of Hospital Medicine (Fakheri and colleagues) argued that routinely prescribing docusate for constipation is not supported by evidence. Docusate remains widely used, especially to avoid straining after surgery or childbirth, but people expecting it to relieve established constipation are often disappointed.

Label Directions

Colace

The Colace 50 mg softgel label says docusate relieves occasional constipation and generally produces a bowel movement in 12 to 72 hours. Adults and children 12 and over take 1 to 6 softgels daily, as one dose or divided; children 2 to under 12 take 1 to 3; under 2, ask a doctor. Do not use if you are taking mineral oil unless told to by a doctor.

MiraLAX

The MiraLAX label lists 17 g of polyethylene glycol 3350 per dose, generally producing a bowel movement in 1 to 3 days. Adults and children 17 and older stir and dissolve one dose in 4 to 8 ounces of any beverage, hot or cold, once a day, making sure no clumps remain. Do not combine with starch-based thickeners used for swallowing difficulty. Do not use more than 7 days unless advised by a doctor; children 16 and under, ask a doctor.

Safety

MiraLAX: do not use if allergic to polyethylene glycol, or if you have kidney disease except under a doctor’s supervision. Ask a doctor first with nausea, vomiting or abdominal pain, or a bowel-habit change lasting over 2 weeks. Stop for rectal bleeding, worsening bloating or cramping, or diarrhea.
Colace: ask a doctor first with stomach pain, nausea, vomiting or a sudden change in bowel habits over 2 weeks. Stop and ask a doctor for rectal bleeding or no bowel movement after use.
Both: stop and see a doctor if you need a laxative for more than 1 week; these can be signs of a serious condition.

When Each Might Fit

Occasional constipation with hard, infrequent stools: polyethylene glycol has the strongest guideline support.
Avoiding straining after surgery, childbirth or with hemorrhoids: docusate is often suggested, though evidence is limited; ask your clinician.
Need faster results: neither is fast; a stimulant such as bisacodyl or senna works overnight. See Dulcolax vs MiraLAX.
Long-term regularity: fiber, fluids and activity first; see MiraLAX vs Metamucil.

Non-Drug Steps

The National Institute of Diabetes and Digestive and Kidney Diseases recommends eating more high-fiber foods, drinking plenty of water and other liquids (especially when adding fiber) and getting regular physical activity, and notes that adults should get 22 to 34 grams of fiber a day depending on age and sex. OTC laxatives are an option when those steps are not enough. Add fiber gradually to limit gas and bloating.

Pregnancy, Children and Older Adults

Both labels say to ask a health professional before use if pregnant or breastfeeding. For children, MiraLAX’s OTC label directs parents of children 16 and under to a doctor, and Colace’s label sets doses only from age 2. Older adults who take several medicines should review constipation-causing drugs (such as opioids, some antacids and anticholinergics) with a pharmacist.

Putting It Together: Common Situations

The scenarios below summarize what the labels and guidelines cited on this page say. They are general information, not a personal treatment plan. Your pharmacist can check the choice against your other medicines, and your clinician can tailor it to your health history.

Occasional constipation: the AGA-ACG guideline strongly recommends polyethylene glycol (the MiraLAX ingredient). Docusate was not among its recommended agents.
Hard stools you want to soften: docusate is labeled as a stool softener, but the evidence that it helps is limited.
Symptoms lasting more than a week: the MiraLAX label says to stop and ask a doctor if you need a laxative for longer than 1 week.

How to Read the Label Before You Buy

Find the active ingredient first. Brand names are often reused across products with different ingredients. The active ingredient and its strength appear at the top of the Drug Facts or Supplement Facts panel.
Check the “Uses” or labeled indication. A product is tested and labeled for specific uses. Using it for something else may not help.
Read the “Do not use” and “Ask a doctor before use” sections. They list conditions and medicines where the product may be unsafe.
Follow the directions for dose and duration. Note the maximum daily amount and how many days you can use it before checking with a clinician.
Check for duplicate ingredients. Combination products can contain the same ingredient as something else you take, which raises the risk of taking too much.
Note the “Stop use and ask a doctor” signs. These are the label’s own warning signs that a product is not working or is causing harm.

Common Mistakes to Avoid

Skipping fiber and fluids. NIDDK lists high-fiber foods, liquids and physical activity as first steps.
Ignoring alarm symptoms. Rectal bleeding, unexplained weight loss or a sudden change in bowel habits need evaluation.
Assuming two products with similar names are interchangeable. Compare the active ingredients and strengths instead of the packaging.
Forgetting to tell your clinician. Keep a current list of every prescription, OTC medicine and supplement you take, and bring it to appointments and the pharmacy.

FormulaCompare does not recommend one brand over another. Use the sources below to check the details for the exact product in front of you, since formulas and labels can change.

When to Talk to Your Doctor or Pharmacist

See a doctor for rectal bleeding, black stools, severe or worsening abdominal pain, vomiting, unexplained weight loss, a change in bowel habits lasting over 2 weeks, or constipation that needs a laxative for more than a week. Seek urgent care if you cannot pass gas or stool and your abdomen is swollen and painful.

Frequently Asked Questions

Is MiraLAX better than Colace?

For relieving constipation, polyethylene glycol (MiraLAX) has a strong recommendation in the 2023 AGA-ACG guideline, while docusate (Colace) was not among recommended agents.

How long does Colace take to work?

The label says it generally produces a bowel movement in 12 to 72 hours.

How long does MiraLAX take to work?

The label says it generally produces a bowel movement in 1 to 3 days.

Can I take Colace and MiraLAX together?

Ask a pharmacist or doctor. There is little evidence that adding docusate improves results.

Is a stool softener the same as a laxative?

Stool softeners like docusate are labeled as laxatives but work by softening stool rather than increasing water in the bowel or stimulating it.

Can I use MiraLAX every day?

The OTC label says not to use more than 7 days unless a doctor advises it.

Sources

Medical disclaimer: This article is for educational purposes and does not replace medical advice. Consult a licensed healthcare provider before starting any supplement, medication, or treatment — particularly if you are pregnant, breastfeeding, taking other medications, or have a diagnosed medical condition.