Rubbing a specific spot just below your knee can stimulate digestive activity and may help relieve constipation. The technique comes from a well-known acupressure point called ST36 (Zusanli), located not on the kneecap itself but about four finger-widths below it. It’s one of the most studied pressure points in the body, and research suggests it activates nerve pathways that promote gut movement.
Why a Point Near Your Knee Affects Your Gut
The connection between your knee area and your bowels isn’t as strange as it sounds. Stimulating points on the limbs activates the parasympathetic nervous system, which is the branch of your nervous system responsible for “rest and digest” functions. The parasympathetic nerves promote the wave-like contractions (peristalsis) that push food and waste through your intestines, while the sympathetic nervous system (your “fight or flight” mode) slows those contractions down.
When you apply pressure to the ST36 point, the signal travels through sensory neurons that connect to the vagus nerve, a major communication highway between your brain and your gut. Animal studies show this stimulation increases the activity of nerve cells in the intestinal wall that release acetylcholine, a chemical messenger that triggers muscles in the gut to contract and move things along. In simpler terms, pressing this spot sends a signal that tells your intestines to get moving.
What the Research Shows
A clinical trial published in Frontiers in Neuroscience tested electrical stimulation at the ST36 point in patients with chronic constipation. After two weeks of daily treatment, participants went from an average of about 1.6 spontaneous bowel movements per week to 5.6, roughly a threefold increase. In the comparison group that received a sham treatment, bowel movements only rose to about 2.8 per week. By the end of the study, 91% of people in the real treatment group were having three or more bowel movements per week, compared to 55% in the sham group.
These results used a small electrical device rather than finger pressure alone, so the effect from manual rubbing or pressing would likely be milder. Still, the underlying nerve pathway is the same, and acupressure (using fingers instead of needles or electricity) has a long history of use for digestive complaints in traditional Chinese medicine.
How to Find and Press the Right Spot
The point you’re looking for isn’t on the kneecap. It’s four finger-widths below the bottom edge of your kneecap and one finger-width to the outside of your shinbone. To find it, sit down and place four fingers horizontally just below your knee. At the bottom edge of your pinky finger, slide slightly toward the outer side of your leg. You’ll feel a small depression in the muscle next to the shin. That’s the spot.
Use your thumb or two fingers to press firmly into this point. You can hold steady pressure for one to two minutes, or use small circular rubbing motions. It should feel like a deep, noticeable pressure but not sharp pain. You can do this on one or both legs. Many practitioners recommend doing it while sitting or lying down in a relaxed position, since relaxation itself supports parasympathetic activity and digestion.
The Knee-to-Chest Position Also Helps
There’s a separate reason people associate knees with pooping. Pulling your knees up toward your chest, whether on the floor as a yoga pose (called Apanasana, or “wind-relieving pose”) or by using a stool to elevate your feet on the toilet, physically compresses your lower abdomen. This gentle pressure massages the abdominal organs, stimulates peristalsis, and helps release trapped gas. It also relaxes the pelvic floor and straightens the angle of the rectum, making it easier for stool to pass.
If you’re on the toilet and feeling stuck, leaning forward and bringing your knees higher than your hips (by resting your feet on a step stool or small box) mimics some of this effect. Combining this position with acupressure on the ST36 point addresses constipation from two angles: mechanical compression from above and nerve stimulation from below.
Who Should Be Cautious
For most people, pressing a point near the knee is completely safe. The one notable exception involves pregnancy. ST36 is considered a “forbidden point” in traditional acupuncture practice before 37 weeks of pregnancy because of theoretical concerns about triggering premature contractions. A systematic review in Medical Acupuncture noted that while the evidence is limited, the routine use of these points before 37 weeks is questionable, particularly for women with a history of preterm delivery, cervical insufficiency, or twin pregnancies. After 36 completed weeks, the same points are sometimes used intentionally to help prepare for labor.
If you have chronic constipation that doesn’t respond to dietary changes, hydration, and movement, acupressure near the knee is a low-risk technique worth trying, but it works best as one tool among several rather than a standalone solution. Fiber intake, adequate water, physical activity, and body positioning on the toilet all contribute to regular bowel movements. Adding ST36 pressure to that routine gives your nervous system one more nudge in the right direction.