The present study was undertaken in an effort to evaluate possible effects of thyroxine, ascorbic acid and L asparagic acid on protein level in the cerebrospinal fluid of chronic schizophrenic patients. 84 chronic schizophrenics whose onset years were not less than four years (average 6.7 years) were randomly divided into four groups of 21. No evidence of organic diseases as well as systematicand syphilitic diseases was found in all cases. Lumbar puncture was performed and the fluid examined for protein. Three groups of patients out of 4 groups then were started on thyroxine 80mg per day, ascorbic acid l,200mg per day and L-asparagic acid 450mg plus thiamin H GI 18mg per day respectively for 30 days. One group was selected \as a controlled one. Repeat lumbar puncture was performed after this series and found no any specific differences between those four groups. Then 8 patients who showed high protein level not less than 5°mg% were chosen and E.E.G.，M.P.T. and neurological examination were performed to reaffirm their diagnoses. Patients were again on medication of thyroxine 180mg per day for a period of 35 days. The mean protein level, pre this course was 58.2 mg% and that of after the course was 36.8mg% and none of 8 patients had a level above 40mg. % However we could not see any clinical inprovement simultanously in these patients whose level became decreased under the upper limit of normality 40mg. % These findings strongly suggested the possible functional hypothyroidism in some group of chronic schronic schizophrenia.