If you’re constipated, the fastest thing you can do right now is drink a full glass of water and try a body position that helps your anatomy work in your favor. Beyond that, the right combination of dietary changes, movement, and (if needed) an over-the-counter laxative can get things moving within hours to a day. Here’s what actually works, starting with what you can do immediately.
Quick Relief: What to Try Right Now
Before reaching for a product, try adjusting your position on the toilet. When you sit on a standard toilet, the muscle that wraps around your rectum only partially relaxes, creating a bend that makes it harder to pass stool. Raising your feet on a small stool or step so your knees are above your hips mimics a squatting position, which straightens the rectum to roughly 100 to 110 degrees and significantly reduces the straining required. This isn’t a gimmick. Imaging studies confirm that squatting creates a straighter path for stool to exit.
While you’re at it, drink a large glass of water. Dehydration makes stool harder and more difficult to pass. If you have prune juice in the house, pour yourself a glass. Prunes contain about 6 grams of sorbitol per 100 grams of juice, a natural sugar alcohol that pulls water into the intestines the same way many commercial laxatives do. This osmotic effect softens stool and triggers the urge to go. Whole prunes are even more potent, with nearly 15 grams of sorbitol per 100 grams.
A warm beverage, particularly coffee, can also stimulate contractions in the colon. Even warm water on its own sometimes helps by relaxing the digestive tract.
Over-the-Counter Laxatives and How Fast They Work
If home remedies aren’t cutting it, OTC laxatives are the next step. They fall into a few categories, and the main practical difference is how quickly they work.
- Magnesium citrate (osmotic/saline laxative): Pulls water into the intestines to soften stool. Typically produces a bowel movement within 30 minutes to 6 hours. Take it with a full 8-ounce glass of water. Don’t use it for more than a week without medical guidance.
- Polyethylene glycol (osmotic laxative): Works more gently by the same water-retention mechanism. Most people have their first bowel movement within one day of starting it.
- Stimulant laxatives (senna, bisacodyl): These directly trigger the muscles of the intestinal wall to contract. They work within 6 to 8 hours when taken orally and often cause some cramping. Best taken at bedtime so they work by morning.
- Lactulose (osmotic, prescription in some forms): Slower acting, with onset between 24 and 72 hours. Better suited for ongoing management than immediate relief.
- Bulk-forming laxatives (psyllium, methylcellulose): These are fiber supplements, not fast-acting solutions. They work by absorbing water and adding bulk to stool, but they take days of consistent use to show results and can actually make things worse if you don’t drink enough water with them.
For a single episode where you need relief today, magnesium citrate or a stimulant laxative is the most practical choice. For recurring constipation, the gentler osmotic options and fiber supplements are better long-term strategies.
The Fiber Fix: How Much You Actually Need
Most people don’t eat enough fiber, and that’s the single biggest dietary driver of constipation. Current guidelines recommend 14 grams of fiber for every 1,000 calories you eat per day. For most adults, that works out to somewhere between 25 and 35 grams daily. The average American gets about half that.
There are two types, and both matter. Insoluble fiber (found in whole grains, vegetables, and wheat bran) adds physical bulk to stool and speeds its passage through the intestines. Soluble fiber (found in oats, beans, apples, and citrus fruits) absorbs water and forms a gel that keeps stool soft and easier to pass. You don’t need to obsess over the ratio. Eating a variety of fruits, vegetables, legumes, and whole grains covers both.
One critical detail: increasing fiber without increasing water will make constipation worse, not better. Research on adults with chronic constipation found that 25 grams of daily fiber significantly increased the frequency of bowel movements, but only when paired with 1.5 to 2 liters of fluid per day. That’s roughly six to eight glasses of water. Fiber without adequate hydration just creates a denser, harder mass in the colon.
If your current fiber intake is low, ramp up gradually over one to two weeks. Jumping from 12 grams to 30 grams overnight tends to cause bloating and gas while your gut bacteria adjust.
Exercise and Gut Motility
Physical activity helps move things through the colon, and the evidence is more specific than “just go for a walk.” A 12-week study measuring colonic transit time (how long it takes food to travel through the large intestine) found that participants doing three 60-minute aerobic sessions per week nearly cut their transit time in half, from about 54 hours down to 30. The control group, which didn’t exercise, showed no change at all.
Shorter exercise programs of one to four weeks haven’t shown the same benefit, which suggests that consistency matters more than intensity. Moderate activity like brisk walking, cycling, or swimming, done regularly, is what makes the difference. Even a 20-minute walk after a meal can stimulate the natural contractions that push stool through the colon, so if you’re constipated today, getting up and moving is worth trying alongside other strategies.
When Constipation Is More Than a Nuisance
Occasional constipation is extremely common and usually resolves with the strategies above. Clinically, constipation becomes a diagnosable condition when you’ve had symptoms for at least three months, with the pattern starting six or more months prior. The formal criteria require at least two of the following in more than 25% of bowel movements: straining, hard or lumpy stools, a feeling of incomplete emptying, a sensation of blockage, needing to use your hands to help pass stool, or having fewer than three spontaneous bowel movements per week.
If that describes your situation, it’s worth investigating further rather than relying on laxatives indefinitely. Chronic constipation can stem from pelvic floor dysfunction, thyroid issues, medications (especially opioids, antidepressants, and iron supplements), or other underlying conditions.
Certain symptoms signal something more urgent. Blood in your stool, unexplained weight loss, vomiting alongside constipation, or severe abdominal pain with prolonged inability to have a bowel movement are red flags. Severe bloating combined with no bowel movements for an extended period can indicate a bowel obstruction, which requires emergency care.