If you need to have a bowel movement and your body isn’t cooperating, there are several approaches that work on different timelines, from minutes to hours. The fastest options involve physical positioning and rectal stimulants, while dietary and behavioral strategies work over the course of a day or two. Here’s what actually triggers a bowel movement and how quickly each method works.
The Fastest Option: Positioning and Physical Techniques
Your body has a muscle that loops around the rectum like a sling, creating a natural kink that helps you stay continent. When you sit on a standard toilet, that muscle only partially relaxes, keeping the passage at an 80 to 90 degree angle. Squatting opens that angle to 100 to 110 degrees, straightening the rectum and making it significantly easier to pass stool. You don’t need to crouch over a hole in the ground. A footstool placed in front of your toilet that brings your knees above your hips mimics a squatting position and can make an immediate difference.
While you’re in position, try an abdominal self-massage called the “I Love U” technique, which follows the natural path of your large intestine. Start by stroking firmly but gently down your left side, from just below your ribs to your left hip bone. Repeat 10 times. Next, trace an “L” shape: across your upper abdomen from right to left, then down the left side. Repeat 10 times. Finally, trace a “U” shape: up from your right hip to your right ribs, across to your left ribs, and down to your left hip. Repeat 10 times. This sequence pushes contents along the colon in the direction they naturally travel.
Use Your Body’s Built-In Triggers
Your colon has a natural clock. Pressure activity in the colon triples immediately after you wake up and again after eating a meal. This is why many people have their most reliable bowel movements in the morning, especially after breakfast. If you’re trying to induce a bowel movement, eating a meal and then sitting on the toilet 15 to 30 minutes later puts you in sync with this reflex.
Coffee accelerates this process. A study published in the journal Gut found that coffee increased movement in the lower colon within four minutes of drinking it, and the effect lasted at least 30 minutes. Interestingly, decaf coffee triggered the same response, suggesting it’s not just the caffeine at work. Hot water alone did not produce the same effect. About 60% of people in the study responded to coffee this way, so it won’t work for everyone, but it’s worth trying if you’re a coffee drinker.
The combination of waking up, eating breakfast, drinking coffee, and then sitting on the toilet with a footstool stacks multiple biological triggers at once. For occasional constipation, this routine alone is often enough.
Foods That Act as Natural Laxatives
Prunes are the classic recommendation, and they earn it. Prunes contain about 14.7 grams of sorbitol per 100 grams (roughly 10 prunes). Sorbitol is a sugar alcohol your body can’t fully absorb, so it pulls water into the intestines and softens stool. Prune juice works too, though it has less sorbitol at 6.1 grams per 100 grams. Eating 5 to 10 prunes or drinking a glass of prune juice can produce results within a few hours to overnight.
Other high-sorbitol fruits include pears, apples, and cherries. Kiwifruit is another strong option, with multiple studies showing it increases stool frequency. Fiber-rich foods like oats, ground flaxseed, and chia seeds absorb water and add bulk that stimulates the colon to contract. The U.S. dietary guidelines recommend 14 grams of fiber per 1,000 calories you eat, and most Americans fall well short of that. If your diet is low in fiber, even a modest increase can make a noticeable difference within a day or two.
Over-the-Counter Options by Speed
If natural methods aren’t cutting it, laxatives work on predictable timelines depending on their type.
- Glycerin suppositories (15 minutes to 1 hour): These are the fastest OTC option. Inserted rectally, they draw water into the lower bowel and trigger a contraction. They’re useful when stool is already in the rectum but you can’t pass it.
- Stimulant laxatives like bisacodyl (6 to 12 hours): These cause the intestinal muscles to contract more forcefully. Taking one before bed typically produces a morning bowel movement.
- Osmotic laxatives like polyethylene glycol (1 to 3 days): These pull water into the colon to soften stool. They’re gentler and better suited for ongoing constipation rather than immediate relief. Saline-type osmotic laxatives work faster, sometimes within 30 minutes to 6 hours.
Magnesium citrate is another popular osmotic option available at most pharmacies. It’s typically taken as a single dose and can work within a few hours. Don’t use it for more than a week at a time, and if you have kidney problems, talk to your doctor first, since your kidneys are responsible for clearing excess magnesium from your body.
What About Drinking More Water?
You’ll see “drink more water” on nearly every constipation list, but the research is more nuanced than you’d expect. A clinical study that had healthy volunteers increase their fluid intake by 1 to 2 liters per day found no significant change in stool output. If you’re already reasonably hydrated, adding extra glasses of water probably won’t move the needle on its own. Where hydration matters most is when you’re genuinely dehydrated, or when you’re increasing your fiber intake. Fiber needs water to do its job. Without enough fluid, adding fiber can actually make constipation worse.
When Constipation Signals Something Bigger
Occasional constipation is extremely common and usually harmless. But certain patterns warrant attention: constipation lasting longer than three weeks, blood in your stool or on toilet tissue, black-colored stools, persistent stomach pain, unexplained weight loss, or unusual changes in the shape of your stool. Any of these alongside constipation should prompt a visit to your doctor, as they can indicate conditions that need evaluation beyond what a laxative can address.