The preparation of penicillin skin test solution is illustrated as follows as an example of 800,000 units. 800,000 penicillin is added to 4 ml of 0.9% sodium chloride injection, 0.1 ml of which is extracted and added to 1 ml of 0.9% sodium chloride injection, 0.1 ml of which is extracted and added to 1 ml of 0.9% sodium chloride injection, and 0.25 ml of which is then added to 1 ml with physiological saline, and 0.1 ml of which is then added to 1 ml, and finally 0.1 ml of which is taken as the top solution to do the skin test. trial, and finally the dosage of penicillin as skin test was 50 units.