Sha(痧)is an acute infectious disease characterised by the appearance of rashes on the skin,caused by exposure to epidemic toxin and pestilent qi.Sha Zhang Yu Heng(《痧胀玉衡》)discussed the treatment principles and methods,and listed collateral bloodletting as one of the main treatments.Through organizing the articles and proved cases,we found that the author believes Sha(痧)is caused by epidemic pathogen,belonging to heat toxin with rapid changes,so timely treatment for qi and blood simultaneously could achieve the effect of transforming qi into defensive qi.Sha Zhang Yu Heng focuses on patient's position during treatmet,the material of the needle,the site of treatment,the quantum of stimulation and the operation of the contraindications and other essentials.According to the depth of the disease location,use traditional Chinese herbal medicine,scraping together to identify the root of the disease.In addition,diet suggestions for the prevention of the recrudescence of disease are also described in detail.