Abstract: 52 cases of adult dermatomyositis Were collected from 1976 to 1981.A detailed study of serum enzymes creatine phosphokinase(CPK),glutamic oxalacetic transaminase(GOT),lactate dehydrogevase(LDH),glutamic pyruvic transaminase(GPT) and aldolase(ALD)is presented,During active stage of the disease,elevated values of serum enzymes are as follows:CPK51.4%,ALD88.9%,GOT 72.2%.LDH96,7% and GPT54.8%.During remission,100% of CPK,93.3% of ALD,69.2% of GOT,40% of LDH and 95.5% of GPT return to normal,The CPK is more specific,but riot very sensitive for dermatomyosiits:The LDH is more sensitive,but less specific for dermatomyositis.The ALD and GOT are the most reliable of serum enzymes and conform best with the clinical course of the disease.The rzlatioa between various grades of patients' impaired muscular function and serum enzyme activity has been studied.The results are as follows:ALD and GOT show highly significant difference(P<0.01);CPK also shows significant difference(P<0.05});while LDH shows no significant difference(P>0.05) between the various grades of impaired muscular function and the levels of serum enzyme activity.After treatment with prednisone,patients' muscle strength improved one grade,in an average period of 2.2 months.The average time required for each serum enzyme to reach normal level is as follows: CPK 50 days,ALD 82 days,GOT 72 days and GPT 77 days.But the normalization of LDH was very slow.These data show that the improvement of muscle strength runs parallel with the descent of serum enzyme levels.Therefore both muscle strength and the level of serum enzyme can be taken as indices of adequacy of treatment,.