Dicang

What is ST4?

ST4, or Dicang, is a Stomach-channel point just beside the corner of the mouth, about a centimetre out from the lip corner.

Its Chinese name is usually translated as "Earth Granary". In classical texts it is one of the main local points for the mouth and cheek, and it appears in every modern acupuncture curriculum. Traditionally it is paired with ST6 at the jaw angle and used for a crooked mouth, drooling and facial pain.

Two things are worth separating before you read any further. Long traditional use tells you that generations of practitioners found a point worth teaching. It does not tell you that the point works, and it does not tell you that the point is safe for you. Safety on the face depends on your skin, your recent dental or surgical history and what is causing your symptom.

The honest verdict on evidence: there is no good human research on finger pressure at ST4 for anything. The point does appear in needling trials for Bell's palsy and facial pain, but those studies are small, poorly blinded and mixed in quality, and they tested needles in prescriptions of several points, not a thumb on one spot. That is a long way from showing that pressing ST4 at home changes a facial nerve problem.

Everything on this page is self-applied finger pressure. Nothing here involves needles, heat or anything that breaks the skin. ST4 sits over thin facial skin and the muscles around the mouth, so the sensible use is light, brief and comfortable contact, approached as self-massage rather than treatment.

The most important point on this page is not about technique. Sudden facial drooping can be a stroke, and new one-sided facial weakness is time-sensitive even when it is Bell's palsy. Pressing a point is never the right first response to either.

Where is ST4 and how do you find it?

ST4 sits about one centimetre to the side of the corner of your mouth, on a line dropped straight down from the pupil when you look forward.

• Find the lip corner. Put a clean fingertip at the exact spot where your upper and lower lips meet at the side. That is your starting landmark.
• Move outward a short step. Slide the fingertip sideways towards the cheek by roughly 0.4 cun. In classical measuring that is a little under half a thumb-width, or about 1 cm on most adult faces.
• Check the pupil line. Look straight ahead in a mirror. ST4 should fall on an imaginary vertical line running down from the centre of your pupil, level with the corner of the mouth.
• Feel the tissue. You are on soft muscle around the mouth, not on bone. Gently purse your lips and you should feel the muscle bunch under your finger.
• Confirm with a smile. Smile widely and a small crease usually forms just outside the lip corner. ST4 lies at or just inside that crease.

A common mix-up is with ST6 (Jiache), the chewing-muscle point at the angle of the jaw, and with ST3 up on the cheekbone below the eye. ST4 is the low one, right next to the lips.

Faces vary, so treat the pupil line as a guide rather than a rule. If your face is narrow or wide, stay with the "just outside the lip corner" landmark, which all sources agree on.

The spot is small, so use a fingertip pad rather than a thumb. Keep your nails short and your hands clean, because this area is close to the mouth. Never state or follow a needle depth for this point; on this page the only contact is a fingertip.

How do you apply pressure to ST4?

1. Wash your hands first. ST4 is beside the mouth, so dirty fingers can carry bacteria to the lips. Short nails matter here more than almost anywhere else.
2. Use the pad of one finger. The index or middle fingertip suits this small spot. Do not use a knuckle, a pen cap or any massage tool on the face.
3. Work both sides. Place one fingertip on each ST4 so your face stays balanced and you are not pulling your mouth to one side.
4. Press lightly. Facial skin is thin. Use only enough pressure to dent the skin slightly, far less than you would use on a shoulder or a foot.
5. Hold or circle briefly. Hold steady, or make small circles, for about 30 to 60 seconds. Keep breathing normally.
6. Repeat once or twice. Two or three short rounds in a session is plenty. One to three sessions a day is a reasonable ceiling.
7. Finish gently. Lift the fingers off slowly and let the skin settle. Avoid dragging or stretching the skin sideways.

Stop straight away if pressing hurts, stings, makes the area numb, or leaves redness that does not fade within a few minutes. Stop too if you feel a lump, a hot swelling or anything tender that you have not felt before.

Give it a fair but limited trial. If nothing has changed after one to two weeks of sensible use, extra pressure or longer sessions will not help. That is the point to stop and ask a clinician about the underlying problem instead.

Never press ST4 hard enough to push your teeth into the inside of your cheek or lip. A small bite injury is the most common harm from overdoing this point.

What is ST4 traditionally used for?

• Facial palsy and a crooked mouth. This is the classical headline use of ST4, usually paired with ST6. Needling trials for Bell's palsy exist, but a Cochrane review of acupuncture for Bell's palsy judged the trials too poor in quality to show benefit or harm. There is no trial of finger pressure at ST4 for it.
• Drooling and dribbling. Tradition links ST4 to control of the lips and to saliva escaping the mouth. Human evidence is essentially absent; reports are case descriptions and clinical opinion, not controlled studies.
• Facial pain, including trigeminal neuralgia. ST4 appears in point prescriptions for pain in the lower face. Reviews of acupuncture for trigeminal neuralgia find small, mostly unblinded studies with mixed results and weak methods, so nothing firm can be claimed.
• Toothache and jaw tension. Local use for lower-face discomfort is long-standing. Any ease from rubbing tense facial muscles is plausible as simple massage, but dental pain has a dental cause that pressure does not treat.
• Twitching around the mouth. Tradition describes ST4 for spasm of the lip muscles. Evidence here is tradition only, with no useful human trials.
• Cosmetic facial massage. ST4 is widely used in "facial rejuvenation" routines. The studies behind these routines are small, uncontrolled and often rely on self-rated photographs, so they prove very little.

Across all of these, the pattern is the same. Tradition is specific and confident; human evidence is thin, short-term and rarely tests pressure rather than needles. Treat ST4 as a comfort measure you add alongside proper care, not as a treatment for the condition itself.

If you have new facial weakness, the useful action is a same-day medical review. Bell's palsy is often treated with steroids, and that window is measured in days.

Are there tips for using ST4 effectively?

• Use a mirror the first few times. It is easy to drift onto the lip itself or up onto the cheekbone. A mirror fixes the landmark quickly, and after a week you will find it by feel.
• Keep the pressure honest. If you are grimacing, you are pressing too hard. Comfortable contact is the standard for every facial point, not a sign you are being too cautious.
• Add a warm flannel first. A warm compress for a minute relaxes the muscles around the mouth and makes the massage more comfortable. It also makes it easier to feel the tissue under your finger.
• Use a little clean oil if the skin drags. A small amount of a plain oil you already tolerate reduces pulling on thin skin. Patch-test anything new elsewhere first.
• Keep sessions short and regular. Two or three brief rounds a day beats one long session. Long sessions mostly produce soreness, not benefit.
• Treat both sides even for one-sided symptoms. It keeps your technique even and stops you repeatedly tugging the mouth in one direction.
• Keep a simple note. Write down what you felt before and after for two weeks. If nothing shifts, that is useful information and a reason to stop.
• Fit it around real treatment. If you are doing facial exercises from a physiotherapist or speech therapist, those come first. ST4 pressure is an optional extra, not a substitute.
• Respect your skin. Skip sessions on days when the area is irritated, sunburnt or newly shaved and sore.

One last practical tip: do this at a time when you can wash your hands properly and will not be eating straight afterwards. Hands near the mouth and food do not mix well.

What do people get wrong with ST4?

• Expecting a cure. ST4 will not cure Bell's palsy, trigeminal neuralgia or a dental problem. Anyone promising that from a point beside your mouth is overselling it badly.
• Delaying medical care. This is the serious one. New facial weakness needs a doctor within days, and sudden drooping with arm weakness or slurred speech needs emergency help now.
• Pressing far too hard. Facial skin bruises easily, and heavy pressure pushes teeth into the inside of the cheek. More force does not mean more effect.
• Landing on the wrong spot. Many people end up on ST6 at the jaw angle or ST3 on the cheekbone. ST4 is the low point, right at the corner of the mouth.
• Pressing over a cold sore or spot. Rubbing a herpes sore or an infected spot can spread it and make it worse. Wait until the skin is intact.
• Using tools on the face. Rollers, gua sha stones and pen caps concentrate force on thin tissue. A fingertip is the right instrument for ST4.
• Copying needling videos. Some clips show a long needle threaded from ST4 towards ST6. That is a practitioner procedure. Nothing about it transfers to self-care, and you should never attempt it.
• Dragging the skin. Pulling sideways stretches the tissue around the mouth instead of applying pressure at the point. Press in and release, do not smear.
• Going on for months. If a fortnight of sensible use changes nothing, the answer is a diagnosis, not more pressing.

A simpler mistake worth naming: not washing your hands. ST4 is a centimetre from your lips, and this is one of the few points where basic hygiene genuinely matters.

What does the research on ST4 actually say?

There is no useful human research on finger pressure at ST4 for any condition. No controlled trial has tested acupressure at this single point, so claims about self-applied ST4 rest on tradition and practitioner experience alone.

What does exist is needling research in which ST4 appears as one point among several. The clearest example is Bell's palsy. A Cochrane systematic review of acupuncture for Bell's palsy pooled the available randomised trials and concluded that their quality was too low to say whether acupuncture helps. Problems included unclear randomisation, no blinding, poor outcome reporting and small numbers. Later trials have been published, but the same weaknesses recur.

Trigeminal neuralgia and other facial pain have a similar picture. Systematic reviews of acupuncture for these conditions find mostly small studies, often from single centres, with weak control conditions and short follow-up. Some report improvement, but the design makes it impossible to separate a real effect from expectation, attention and natural recovery.

Two further limits matter here. First, these were needling studies, and conclusions about needles do not transfer to a fingertip. Second, they used point combinations, so even a positive result would not tell you what ST4 itself contributed.

Facial palsy also recovers on its own in a large share of cases, often within weeks. That makes uncontrolled reports and personal testimonials particularly unreliable, because improvement would have happened anyway.

So the honest grade is "insufficient" on evidence, while the traditional standing of ST4 is as high as it gets. That mismatch is normal for individual acupoints and it is not a reason to hide either half of it.

Practically, this means you can use gentle ST4 pressure as comfort or self-massage if you enjoy it, with no expectation attached. It is not a reason to postpone assessment of any new or worsening facial symptom.