Most constipation responds well to a combination of dietary changes, more fluids, and over-the-counter products you can pick up at any pharmacy. The right choice depends on how quickly you need relief and whether this is a one-time problem or something that keeps coming back.
Start With Fiber and Fluids
Fiber is the simplest long-term fix. It works by absorbing water in your gut, which makes stool bulkier and softer so it moves through more easily. The recommended daily intake is about 25 to 28 grams for women and 28 to 34 grams for men, depending on age. Most people fall well short of that.
Good food sources include beans, lentils, whole grains, vegetables, and fruit. But three foods stand out in clinical testing: green kiwifruit, prunes, and psyllium husk (the fiber in products like Metamucil). A randomized trial published in The American Journal of Gastroenterology compared two kiwis per day, 100 grams of prunes per day, and 12 grams of psyllium per day in people with chronic constipation. All three significantly increased bowel movement frequency within four weeks, and all three reduced straining. Kiwifruit and prunes also improved stool consistency. If you’re not a supplement person, two kiwis or a handful of prunes daily is a reasonable place to start.
Fluid intake matters more than people realize, especially when you’re adding fiber. A study on adults with chronic constipation found that a high-fiber diet worked significantly better when paired with 1.5 to 2 liters of water per day. Fiber without enough fluid can actually make things worse, because the fiber absorbs water from your intestines and can harden stool further.
Over-the-Counter Laxatives
If diet changes alone aren’t enough, several categories of OTC laxatives are available. They differ in how they work and how fast they act.
Osmotic Laxatives
Polyethylene glycol (sold as MiraLAX and store-brand equivalents) is the only OTC laxative that received a strong recommendation for chronic use from the joint American Gastroenterological Association and American College of Gastroenterology guidelines. It works by pulling water into your intestines, softening stool and adding bulk. You mix a measured dose into a glass of water once a day. Expect results in one to three days. It’s tasteless, doesn’t cause cramping for most people, and is considered safe for extended use.
Magnesium citrate is another osmotic option that acts faster, sometimes within 30 minutes to six hours. It’s more potent and better suited as an occasional solution rather than a daily one. Magnesium oxide is absorbed less readily, which means more of it stays in the gut to draw in water. If you’re trying magnesium for the first time, start with a low dose and increase gradually.
Fiber Supplements
Psyllium husk is the most studied fiber supplement for constipation. It absorbs water, increases stool bulk, and stimulates the natural contractions that move things along. It typically takes 12 hours to three days to work. You need to drink a full glass of water with each dose. Methylcellulose is a similar option for people who find psyllium causes too much gas.
Stimulant Laxatives
Bisacodyl (Dulcolax) and senna work by triggering contractions in your intestinal wall, which speeds stool through the colon. They’re the fastest-acting oral option, producing a bowel movement in 6 to 12 hours. Clinical guidelines give bisacodyl a strong recommendation for short-term use (under four weeks) or as rescue therapy when gentler options haven’t worked.
Long-term use of senna and other anthraquinone-based stimulant laxatives can cause a harmless darkening of the colon lining called melanosis coli. It reverses within 6 to 12 months after stopping. Despite older fears, there is no evidence linking stimulant laxative use to colon cancer in humans. Still, these are best used occasionally rather than daily for weeks on end. Overuse of any stimulant laxative can lead to electrolyte imbalances and a reliance on the laxative to have a bowel movement.
Stool Softeners
Docusate sodium (Colace) works as an emollient, helping water mix into hard stool to soften it. It takes 12 hours to three days. Stool softeners are the gentlest option, but also the least effective for moderate to severe constipation. They’re most useful when you want to prevent straining, such as after surgery or during pregnancy, rather than to treat significant backup.
A Practical Order of Operations
Think of constipation relief in tiers. First, increase your fiber intake through food or a psyllium supplement, drink at least 1.5 to 2 liters of water daily, and add regular physical activity. If that doesn’t produce results within a few days, try an osmotic laxative like polyethylene glycol daily. If you need faster relief while waiting for the osmotic to kick in, a stimulant like bisacodyl can bridge the gap. Use stool softeners when the issue is hard stool specifically, not infrequent bowel movements.
Prescription Options for Chronic Constipation
When OTC products don’t solve the problem after a reasonable trial, prescription medications are the next step. These work by increasing fluid secretion into the intestines, which softens stool and stimulates movement. The American Gastroenterological Association strongly recommends three prescription options for chronic constipation that hasn’t responded to over-the-counter treatment. All three have been shown to be significantly more effective than placebo in clinical trials with moderate-quality evidence. A fourth option works by directly stimulating the gut’s motility, essentially speeding up how fast your colon moves things along. Your doctor can determine which is the best fit based on your symptoms and response to previous treatments.
Signs That Constipation Needs Attention
Occasional constipation is common and rarely serious. But if you don’t typically have problems and constipation lasts longer than a week, it’s worth making an appointment. Certain symptoms alongside constipation point to something that needs evaluation: blood in your stool, unexplained weight loss, or vomiting. Severe abdominal pain combined with a prolonged inability to have a bowel movement is a reason to go to the emergency room, as this can signal a bowel obstruction.