Most constipation resolves with a few straightforward changes: more fiber, more water, more movement, and better toilet posture. If those don’t work within a few days, over-the-counter laxatives can help. Here’s what actually works, how fast each option kicks in, and how to combine them for the best results.
Eat More Fiber (and the Right Kind)
Fiber is the single most effective dietary fix for constipation. Current guidelines recommend 14 grams of fiber for every 1,000 calories you eat, which works out to roughly 25 to 30 grams a day for most adults. The average American gets about half that.
There are two types, and both help in different ways. Soluble fiber absorbs water and turns into a gel during digestion, which softens your stool. Insoluble fiber adds bulk and speeds the passage of food through your intestines. Most plant foods contain a mix of both, so you don’t need to obsess over which type you’re eating.
The highest-fiber foods per serving are legumes. A cup of cooked split peas delivers 16 grams, lentils provide 15.5 grams, and black beans come in at 15 grams. If beans aren’t your thing, these options add up fast:
- Raspberries: 8 grams per cup
- Green peas: 9 grams per cup
- Chia seeds: 10 grams per ounce
- Whole-wheat pasta: 6 grams per cup
- Broccoli: 5 grams per cup
- Pears: 5.5 grams each
- Bran flakes: 5.5 grams per three-quarter cup
One important caveat: increase fiber gradually over a week or two. Adding too much too quickly can cause bloating and gas, which makes an already uncomfortable situation worse. Pair every increase in fiber with extra water.
Drink Enough Water
When your body is low on fluids, the colon compensates by pulling more moisture out of stool before it passes. That’s what makes stool hard, dry, and painful to move. Staying well-hydrated lets the colon absorb just the right amount of water, keeping stool soft enough to pass easily.
There’s no single magic number for how much water fixes constipation, because the right amount depends on your size, activity level, and climate. A reasonable starting point is to drink enough that your urine stays pale yellow throughout the day. If you’re adding fiber to your diet, you need even more water than usual, because soluble fiber works by drawing water into your stool. Without enough fluid to draw from, extra fiber can actually make things worse.
Move Your Body
Physical activity stimulates the wave-like contractions (peristalsis) that push stool through your colon. It also triggers the body to produce compounds called prostaglandins, which further promote intestinal movement. The net effect is a shorter transit time, meaning food waste spends less time sitting in your colon losing moisture.
You don’t need an intense workout. A brisk 20- to 30-minute walk is often enough to get things moving, especially if you’ve been sedentary. Many people find that a walk after a meal is particularly effective, since your digestive system is already active.
Fix Your Toilet Posture
A standard toilet seat puts your body at a 90-degree angle, which partially kinks the rectum. A muscle called the puborectalis stays flexed in this position to prevent stool leakage, but it also makes evacuation harder. You end up straining, which over time can contribute to hemorrhoids and incomplete bowel movements.
Placing a footstool (6 to 9 inches tall) under your feet while sitting on the toilet changes the angle of your hips to something closer to a squat. This relaxes the puborectalis muscle, straightens the path between your rectum and anus, and lets stool pass with significantly less effort. Leaning your torso slightly forward amplifies the effect. It’s a free, immediate change that many people notice on the first try.
Over-the-Counter Laxatives
If lifestyle changes haven’t produced results within a few days, laxatives are the next step. They come in three main categories, each working differently and on a different timeline.
Bulk-Forming Laxatives
These are essentially concentrated fiber supplements. Products like Metamucil (psyllium) and Citrucel (methylcellulose) add soluble fiber to your stool, drawing in water to make it larger and softer. The increased size triggers your colon to contract and push things along. They’re the gentlest option but also the slowest, typically taking 12 to 72 hours to work. Drink plenty of water with them.
Osmotic Laxatives
These pull water from surrounding tissues into your colon, softening stool so it’s easier to pass. MiraLAX (polyethylene glycol) is the most commonly used and generally takes one to three days. Saline versions like Milk of Magnesia work faster, sometimes within 30 minutes to 6 hours. Osmotic laxatives are a good middle-ground option for occasional use.
Stimulant Laxatives
Products containing bisacodyl or senna activate the nerves controlling your colon muscles, forcing contractions that move stool out. They work within 6 to 12 hours and are the most powerful over-the-counter option. Because they work by essentially overriding your colon’s natural rhythm, they’re best reserved for short-term use when gentler options haven’t worked.
Magnesium Citrate for Stubborn Cases
Magnesium citrate is a liquid osmotic laxative that works relatively quickly and is available without a prescription. It’s often used when other options have failed. The standard approach is a single dose (following the label directions), and it should not be used for more than one week unless a doctor says otherwise. People with kidney disease or those on sodium- or magnesium-restricted diets should avoid it without medical guidance. If you’ve had stomach pain, nausea, or a sudden change in bowel habits lasting more than two weeks, talk to a doctor before using it.
Probiotics for Regularity
Probiotics won’t provide fast relief, but they can help with ongoing regularity. A large meta-analysis published in BMJ Open found that probiotic products increased stool frequency by roughly one additional bowel movement per week compared to placebo, and also improved stool consistency. Products combining probiotics with prebiotics (called synbiotics) performed better than probiotics alone. Strains in the Bifidobacterium family have been the most studied for constipation, though multi-strain products showed promising results as well. Think of probiotics as a long-term supporting strategy rather than a quick fix.
Red Flags That Need Medical Attention
Most constipation is temporary and harmless, but certain signs point to something more serious. Blood in your stool, severe abdominal pain, constipation lasting longer than three weeks, unexplained weight loss, or a sudden, lasting change in your bowel pattern all warrant a visit to a healthcare provider. This is especially true if you’re over 50 or have a family history of colorectal problems.