Several types of medicine can help you poop, ranging from fiber supplements and stool softeners to stronger stimulant laxatives and prescription options. The right choice depends on how long you’ve been constipated, how severe it is, and what’s causing it. Most people find relief with over-the-counter options, and many work within hours to a couple of days.
Osmotic Laxatives: The Strongest Recommendation
Polyethylene glycol 3350 (sold as MiraLAX) is the only over-the-counter constipation treatment that received a strong recommendation for ongoing use in the joint American Gastroenterological Association and American College of Gastroenterology guidelines. It works by pulling water into your intestines, which softens stool and makes it easier to pass. You mix the powder into a drink and take it once daily. Most people have a bowel movement within one to three days of starting it, though it can take longer to reach full effect.
Lactulose is another osmotic option, available by prescription in the U.S. but over the counter in some countries. It works the same basic way, drawing water into the colon. Magnesium oxide, often sold as a supplement, also has osmotic effects and was suggested as a reasonable option in the same guidelines, though with weaker supporting evidence.
Stimulant Laxatives: Fast-Acting Relief
Bisacodyl (the active ingredient in Dulcolax) and senna (found in Senokot and Ex-Lax) directly trigger the muscles in your intestinal wall to contract, physically pushing stool along. They’re the go-to when you need results relatively quickly. Bisacodyl tablets produce a first bowel movement in roughly 6 to 12 hours on average, which is why many people take them at bedtime and expect results by morning.
Clinical guidelines strongly recommend bisacodyl for short-term use (under four weeks) or as “rescue therapy” when gentler options haven’t worked. Senna received a conditional recommendation, meaning it’s a reasonable choice depending on your situation. The old worry that stimulant laxatives damage the colon or cause dependency has been largely debunked. At recommended doses, the risk of serious side effects like dehydration or electrolyte problems is negligible. Chronic senna use can cause a harmless, reversible darkening of the colon lining called pseudomelanosis coli, but this has no functional significance.
Fiber Supplements: The Gentle First Step
Psyllium husk (Metamucil) is the most commonly recommended bulk-forming laxative. It absorbs water in your gut and forms a gel-like mass that adds bulk to your stool, stimulating your intestines to move things along naturally. The standard dose is one rounded teaspoon (about 3.4 grams) mixed into 8 ounces of liquid, taken up to three times daily. If you’re new to fiber supplements, start with one serving a day and gradually increase to avoid bloating and gas.
Fiber supplements are the slowest option. They can take two to three days to produce noticeable results, and they work best when you drink plenty of water alongside them. They’re not the right pick if you need immediate relief, but they’re a solid long-term strategy for people who deal with constipation regularly. Methylcellulose (Citrucel) is an alternative for people who find psyllium too gassy.
Stool Softeners: Popular but Questionable
Docusate sodium (Colace) is one of the most widely purchased constipation remedies, but the evidence behind it is surprisingly weak. A review of clinical studies found that docusate was no more effective than placebo at increasing stool frequency, softening stool, or reducing the difficulty of passing a bowel movement. In one study of cancer patients, those taking senna alone actually had more bowel movements than those taking senna plus docusate.
Stool softeners work by letting water mix into hard stool, at least in theory. In practice, if you’re choosing between a stool softener and an osmotic or stimulant laxative, the evidence favors the latter two. Docusate does have a good safety profile, including during pregnancy, which is one reason it remains popular despite the underwhelming data.
Prescription Options for Chronic Constipation
If you’ve tried over-the-counter options without success, prescription medications are the next step. Three drugs received strong recommendations in clinical guidelines: linaclotide (Linzess), plecanatide (Trulance), and prucalopride (Motegrity). Each takes a different approach.
Linaclotide and plecanatide both increase the flow of fluid into your intestines, which speeds up transit and softens stool. Linaclotide has the added benefit of reducing abdominal pain, making it particularly useful for people whose constipation comes with cramping or bloating. Both are taken as a daily pill on an empty stomach. Prucalopride works differently: it stimulates the natural rhythmic contractions of your colon, essentially speeding up the movement of stool through your system.
Lubiprostone (Amitiza) is another prescription option that increases fluid secretion in the intestines, though it received a weaker recommendation due to lower-quality evidence. It’s taken twice daily with food. All of these prescription medications are typically reserved for chronic idiopathic constipation, the kind that persists for months without a clear underlying cause.
Medicines for Opioid-Induced Constipation
Constipation caused by opioid pain medications is a distinct problem that often doesn’t respond well to standard laxatives. Opioids slow down the entire digestive tract by activating receptors in the gut wall, and regular laxatives don’t address that root cause.
A class of prescription drugs called PAMORAs was designed specifically for this situation. These include methylnaltrexone, naldemedine, and naloxegol. They block opioid receptors in the gut without crossing into the brain, so they relieve constipation without interfering with pain relief. This is the key distinction: your pain medication keeps working while your digestive system gets unblocked. Methylnaltrexone is available as both a pill and an injection, while naldemedine and naloxegol are oral only. If you’re on long-term opioids and struggling with constipation despite trying fiber and osmotic laxatives, these are worth discussing with your prescriber.
Suppositories and Enemas: When You Need Results Now
Rectal options work faster than anything you swallow. Glycerin suppositories lubricate and mildly stimulate the rectum, typically producing a bowel movement within 15 to 60 minutes. Bisacodyl is also available as a suppository, which acts faster than the oral tablet because it stimulates the colon directly. Fleet enemas, which contain a saline solution, work within 2 to 15 minutes by flooding the lower colon with fluid.
These are useful for acute situations when you’re uncomfortable and need fast relief, but they’re not meant for routine use. Frequent enema use can disrupt the electrolyte balance in your body, particularly sodium and phosphate levels.
Constipation During Pregnancy
Up to 40% of pregnant women experience constipation, and the options narrow somewhat during pregnancy. The recommended first step is increasing dietary fiber, water intake, and daily exercise. When that’s not enough, bulk-forming agents like psyllium are considered the safest medication option because they aren’t absorbed into the bloodstream. Docusate sodium, despite its limited efficacy data, has not been linked to adverse effects during pregnancy and is also considered safe.
Osmotic and stimulant laxatives can be used during pregnancy but are recommended only occasionally or short-term to avoid dehydration or electrolyte imbalances. Mineral oil is poorly absorbed and doesn’t appear to cause problems, but it can interfere with the absorption of fat-soluble vitamins if used long-term.
How to Choose the Right Option
For occasional constipation that just started, a stimulant laxative like bisacodyl or senna will give you the fastest oral relief. If constipation is a recurring pattern, an osmotic laxative like polyethylene glycol is a better daily strategy, with fiber supplements as a reasonable long-term addition. Skip the stool softener unless you have a specific reason to use one, since the evidence doesn’t support it as an effective standalone treatment.
If over-the-counter options haven’t worked after a few weeks of consistent use, prescription medications like linaclotide or prucalopride are the established next step. Blood in your stool, unexplained weight loss, or constipation lasting longer than three weeks warrants a conversation with a healthcare provider to rule out something more serious.