Best laxative for constipation

A curated shortlist, over-the-counter and prescription. Standing in the pharmacy aisle instead? The over-the-counter shelf for constipation, product by product →

By the pharmaranks editorial teamReviewed against FDA, NHS & MedlinePlus sourcesUpdated Jun 30, 2026How we research

Occasional constipation is almost always self-care: most people get better by drinking more fluids, gradually adding fiber, staying active, and—if needed—using an over-the-counter laxative, with the most common type (bulk-forming fiber) recommended to try first. Laxatives are meant for short-term use; persistent or severe symptoms should be checked by a clinician.

What constipation is, how it is treated, and every drug we rate for it →

For options we rate, we show our independent FDA recall-safety rating(0–100) — a signal GoodRx and Drugs.com don’t provide. Higher is safer.

Over-the-counter options

Available without a prescription — follow each label.

psyllium (ispaghula husk) Metamucil, Fybogel Bulk-forming laxative (fiber)	NHS-recommended first choice to buy without a prescription. Absorbs water to make stool bulkier and softer so the bowel can push it out. Best for mild, ongoing constipation; take with plenty of water. Works in up to about 3 days.
methylcellulose Citrucel Bulk-forming laxative (fiber)	Another bulk-forming fiber option that pulls water into the intestines to form a bulkier, easier-to-pass stool. Good for gently increasing daily fiber; must be taken with adequate fluids.
polyethylene glycol 3350 MiraLAX Osmotic laxative Our rating 56/100	Draws water into the bowel to soften stool and make it easier to pass. A good choice for occasional constipation when stool is hard and dry. May take 2–4 days to produce a bowel movement (per MedlinePlus).
magnesium hydroxide Milk of Magnesia Saline/osmotic laxative	Pulls water into the bowel for short-term relief of occasional constipation in adults and children. Works fairly quickly; use short-term only and follow label dosing.
docusate sodium Colace Stool softener	Lets more water and fat enter the stool to make it softer and more slippery. Best when the goal is to avoid straining (e.g., after surgery or childbirth, or with hemorrhoids) rather than for severe constipation.
bisacodyl Dulcolax Stimulant laxative	Triggers the bowel muscles to push stool out; faster-acting (oral roughly 6–12 hours; rectal suppository within about an hour). Useful for short-term relief when gentler options haven't worked. Not for routine daily use.
senna (sennosides) Senokot Stimulant laxative	Plant-based stimulant that increases bowel activity to produce a bowel movement, usually overnight. For short-term use only; long-term reliance is discouraged.

Prescription options

A doctor may prescribe these — not for self-treatment.

linaclotide Linzess Guanylate cyclase-C agonist Our rating 70/100	A doctor may prescribe this for chronic idiopathic constipation or IBS with constipation (IBS-C) when OTC measures aren't enough. It increases fluid in the intestines and speeds transit. Prescription only; per MedlinePlus, children under 2 should never take it.
lubiprostone Amitiza Chloride channel activator	A doctor may prescribe this for chronic constipation, IBS-C, or opioid-induced constipation when over-the-counter laxatives and lifestyle changes have failed. It increases intestinal fluid secretion to ease passage. Prescription only and chosen/monitored by a clinician.
plecanatide Trulance Guanylate cyclase-C agonist	A doctor may prescribe this for chronic idiopathic constipation or IBS-C in adults. Like linaclotide, it boosts intestinal fluid to improve bowel movements. Prescription only.
prescription-strength polyethylene glycol / other agents Osmotic and other prescription laxatives	For stubborn or opioid-induced constipation, a clinician may prescribe a stronger or different regimen (including specific agents for opioid-induced constipation) after reviewing your medicines and other causes. These are tailored to the individual—do not self-prescribe.

Just want the drugstore answer?

If you are standing in the pharmacy aisle rather than deciding whether to see a clinician, our deeper page on what actually works over the counter for constipation takes each product one at a time: how strong the evidence is, the limits printed on its own label, and when an OTC product is the wrong answer entirely.

How to choose

Start with lifestyle measures: drink more fluids (about 8–10 cups/2–2.5 L of water a day if appropriate for you), increase fiber gradually to avoid bloating, stay active, and don't ignore the urge to go. If you need a laxative, the NHS suggests trying a bulk-forming fiber (psyllium/methylcellulose) first, with plenty of water. If stool is hard and dry, an osmotic laxative (polyethylene glycol or magnesium hydroxide) softens it well. A stool softener (docusate) is best when the priority is avoiding straining—after surgery, childbirth, or with hemorrhoids. Reserve fast-acting stimulants (bisacodyl, senna) for short-term relief when gentler options haven't worked, and don't rely on them daily. A pharmacist can help you choose. Don't use any laxative for more than about a week without talking to a provider, and review with your doctor whether another medicine (e.g., opioids, iron, some antidepressants) is contributing. The prescription medicines listed here are decided and monitored by a clinician—do not self-prescribe them.

When should I see a doctor?

See a doctor if constipation lasts despite treatment, keeps coming back, or if you have a sudden, unexplained change in your normal bowel habits. Seek prompt medical care for any red-flag symptoms: blood in your stool or black/tarry stools, unexplained weight loss, persistent or severe abdominal pain or bloating, ongoing nausea or vomiting, or no bowel movement for several days especially with belly pain. Also check in if a medication you take seems to be causing constipation, or if a child or older adult has persistent symptoms. Constipation with severe pain, vomiting, and an inability to pass stool or gas can signal a bowel obstruction—seek urgent care.

Before you combine anything

Check drug interactions →Any recent recalls? →

Sources

General reference, not medical advice, and not a substitute for your doctor or pharmacist. The right choice depends on your symptoms, health conditions, age, and other medicines — always read each label and confirm before taking anything.

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