For over thousands of years, acupuncture has been an effective way of health-preservation and treating problems. Shower or not after acupuncture treatment is actually a question about preventing skin infection around needling holes.
The awareness of shower or bath after an acupuncture treatment is to prevent the invasion of wind cold dampness. Avoiding the invasion of wind cold dampness is very important part of TCM health-preservation. Wind cold dampness are major external pathogens causing a variety of health problems. One has to avoid the invasion of wind cold dampness all time, not only after an acupuncture treatment.
As to how long after a treatment one can shower, this has something to do with individual situations. Generally speaking, if only filiform acupuncture needles are used in treatment, it's ok to shower after 2 hours. To those who have sensitive skin and are subject to infection, shower after half day.
Acupuncture treatment is a broad term and it may include some other modalities such as fire needling, blood-letting etc. So I will say, usually 2 hours after an acupuncture treatment involving just filiform needles are safe.
If there are other bigger needling holes on skin, such as bigger holes from bloodletting, wait longer to shower. If the patient is under general good health condition, without obvious infection and lower immunity, he can shower the next day. If the patient does not feel as good, he can shower after 2 days. If the patient has diabetes and low immunity, shower after 3 days.
To sum up, it is individual situations that decide it. Also, one can take a standing shower for a bit longer time; a bath has to be shorter to avoid the risk of skin infection.
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