The most effective over-the-counter option for most people is fiber supplementation or polyethylene glycol (sold as MiraLAX and store-brand equivalents). The American Gastroenterological Association recommends both as first-line treatments for chronic constipation, and they work through different mechanisms, so the right choice depends on whether you need a daily habit or faster relief.
Fiber Supplements
Psyllium husk is the most studied fiber supplement for constipation. It absorbs liquid in the intestines, swells, and forms a bulky, soft stool that’s easier to pass. You take it one to three times daily, mixed into water or another liquid. It’s not a quick fix. Fiber works best as a daily habit over days to weeks, gradually training your bowel into a more regular pattern.
The key detail most people miss is water intake. Fiber without enough fluid can actually make constipation worse. Research published in the Journal of the Academy of Nutrition and Dietetics found that psyllium’s effects “increase tremendously” when taken at higher doses with adequate water, recommending at least 500 mL (about 17 ounces) of water per dose. At minimum, drink a full tall glass of water every time you take a fiber supplement.
Current dietary guidelines recommend 14 grams of fiber per 1,000 calories you eat. Most Americans fall well short of that. If you’re not getting enough fiber from food, a supplement bridges the gap, but increasing fiber-rich foods (beans, lentils, whole grains, berries, pears) is the more sustainable long-term approach. Prunes are a particularly effective food choice because they contain both fiber and a natural sugar alcohol that draws water into the intestine.
Polyethylene Glycol (MiraLAX)
Polyethylene glycol 3350 is an osmotic laxative, meaning it pulls water into the colon to soften stool and stimulate a bowel movement. The standard dose is about one heaping tablespoon, dissolved in any beverage once daily. It typically takes two to four days to produce a bowel movement, so don’t expect same-day results. This is the option gastroenterologists most commonly recommend for ongoing constipation that doesn’t respond to fiber alone, and it’s considered safe for longer-term use under a doctor’s guidance.
Magnesium Citrate
Magnesium citrate is a saline laxative sold as a liquid in most pharmacies. It works by pulling water into the intestines, similar to polyethylene glycol but typically faster and more powerful. The adult dose is 6.5 to 10 fluid ounces, taken with a full 8-ounce glass of water. It’s best suited for occasional use when you need more immediate relief rather than as a daily supplement. Expect results within a few hours. Because it can cause cramping and loose stools, start on the lower end of the dose range.
Stimulant Laxatives
Stimulant laxatives like bisacodyl (Dulcolax) and senna work by triggering the muscles in your intestinal wall to contract and push stool along. They’re the strongest over-the-counter option and the fastest-acting. Bisacodyl suppositories work within 10 to 45 minutes. Oral tablets take longer, usually 6 to 12 hours, which is why many people take them at bedtime for a morning result.
The important rule with stimulant laxatives: do not use them daily for more than five days. Your body can become dependent on them, meaning your bowels stop doing the work on their own. These are a short-term rescue option, not a maintenance strategy. If you find yourself reaching for them regularly, that’s a sign to try fiber or an osmotic laxative instead.
Skip the Stool Softeners
Docusate sodium (Colace) is one of the most commonly purchased constipation products, and it’s also one of the least effective. A comprehensive review in The American Journal of Gastroenterology examined seven randomized, placebo-controlled trials and found that none of them showed a significant difference between docusate and a placebo for softening stool. A separate trial of 170 patients compared docusate directly against psyllium for increasing stool water content. Docusate had no measurable effect, with stool water staying below 72%, which still qualifies as hard stool. The researchers concluded bluntly: “It is a misconception that docusate softens hard stool in constipation.” Save your money and choose one of the options above.
A Practical Starting Plan
If you’re dealing with occasional constipation, start with the gentlest approach and escalate only if needed. Begin with a daily fiber supplement (psyllium) taken with plenty of water, and increase your dietary fiber at the same time. Give this at least a week. If that’s not enough, add polyethylene glycol daily. If you need faster one-time relief, magnesium citrate or a bisacodyl suppository will work within hours.
For constipation that keeps coming back, the pattern matters more than the product. Regular fiber intake, consistent hydration, physical activity, and not ignoring the urge to go all contribute to keeping things moving. The supplement is a tool, but it works best alongside those habits.
Signs That Need Medical Attention
Most constipation responds to the options above within a few days. But if you notice blood in your stool, have severe abdominal pain, or your constipation lasts longer than three weeks despite trying these remedies, those are signals to get evaluated rather than continuing to self-treat.