0.5–1 cun vertically or slightly obliquely towards the palmar aspect of the hand.
Caution: Reducing Needle techniques are contraindicated during pregnancy, except being used for inducing labor.
Hegu LI-4 is one of the most important point to expel Wind-Heat and release the Exterior by stimulating the diffusing of Lung Qi. Therefore, it is widely used in the starting stages of a common cold, influenza, allergic rhinitis or other Exterior diseases. The typical manifestations are blocked nose, sneezing, burning eyes, coughing, stiff neck or aversion to cold.
Due to its strong function of extinguishing Wind from the head, some practitioners use the combination of LI-4 and Taichong LIV-3 for stopping headache. Actually the combined bilateral needling of these two points is called 'Si Guan' (Four Gate). They strongly regulate Qi and Blood, stop pain and relieve spasms.
Furthermore, when used together with Taichong LIV-3, Shenting DU-24 and Benshen GB-13, LI-4 is said to be also effective in calming the Mind and reducing anxiety. It is commonly practiced in the Western countries.
It also regulates sweating by regulating Defensive Qi in the space between the skin and muscles. Therefore, in case of Wind invasion, it is effective in both occasions of excessive or absence sweating. Tonifying Hegu LI-4 and reducing Fuliu KI-7 to stimulate sweating. Vice versa to stop sweating.
When combined with Zusanli ST-36 and Qihai REN-6, it is able to treat chronic allergic rhinitis due to Lung Qi Deficiency or just general weak Defensive Qi. The patients are more likely to be effected by Exterior Wind Invasion.
Due to its direct influence on face, it is often used as a distal point to treat diseases related to mouth, nose, ears and eyes. Typical symptoms are allergic rhinitis, conjunctivitis, mouth ulcers, styes, sinusitis, epistaxis, toothache, trigeminal neuralgia or frontal headaches. It is also used for facial problems after Wind-stroke, such as deviation of eye and mouth or peripheral facial paralysis.
It is also a powerful distal point in treating Painful Obstruction Syndrome in the finger, arm or shoulder as it opens the Channel. In additional to that, it also eases pain in Organs, especially in the Stomach, Small and Large Intestine and Uterus due to its calming and antispasmodic function.
Another important function of LI-4 is to harmonize the Yang ascending and Yin descending. Therefore, it can subdue uprising Rebellious Qi or lift sinking Qi. For example, Rebellious Stomach Qi causes epigastric pain, Liver Yang rising causes migraine while Rebellious Lung Qi leads to asthma. When used together with Qihai REN-6, it can raise sinking Spleen Qi.
Finally, Hegu LI-4 is said to be powerful in inducing labor. Thus it can be used for prolonged or delayed labor as well as retention of dead fetus. Therefore, it is forbidden to use during pregnancy.