Many phychiatrists have reported that the change of serotonin concentration would cause mental disorder and affect the pathological conditions such as schizophrenia, depression and eating behabior. The end product of serotonin metabolism was excreted as 5-HIAA in urine. Serum lipids, according to the report, were concerned with obesity, said it was. This study aims to observe the changes of plasma serotonin, urinary 5-HIAA and serum lipids, making use of Fat Cell Mass rate of 27 normal persons and 42 psychosomatic patients. For this, I also observed the change of serotonin, 5-HIAA and lipids of the psychosomatic patients by the use of 3 kinds of herbs as treatment medication on the basis of physical symptoms and the results were obtained as follows; 1. Urinary 5-HIAA is correlated with the body water rate(r=0.381), while reversely correlated with the Fat Cell Mass rate(r=-0.330). 2. Compared the control group with the patients group for the serum lipids value, they showed the significant results ; $146.4{pm}5.71$ mg/dl and $166.9{pm}6.56$ mg/dl in the total cholestrol value over- weights, $471.2{pm}42.99$ mg/dl in the total lipid value, and $158.1{pm}6.50$ mg/dl and $181.1{pm}6.30$ mg/dl in the phospholipid of the obesity, respectively. 3. With comparison of each group to other group to the others for Fat Cell Mass rate, the total cholesterol showed the significant differences when the Fat Cell Mass rate was 20% or more, HDL-cholesterol value when 30% or more, and triglyceride when 30% or more, respectively. 4. there was significant variations in the relations between Fat Cell Mass rate and body water, which body mass index was increased as the body water was decreased. 5. Fat Cell Mass rate was correlated with Cholesterol(r = 0.420), triglyceride (r = 0.443), and $eta$-lipoprotein(r = 0.450) of serum lipids, while reversely correlated with HDL -Cholesterol(r = -0.354) and urinary 5- HIAA had the correlation coefficient of -0.330. 6. What related with body water rate urinary 5-HIAA (r = 0.381) and $eta$-lipoprotein(r = -0.405). 7. there were significant changes in the total cholesterol value and HDL-Cholesterol Value of serum lipids after dose of Ondamtang, significant increase in the 5-HIAA value after dose of Samulansintang, and significant devrease in the Trigylceride value of serum lipids after dose of Shihosogansan. As a result, it was seen that there was direct correlations among the Fat Cell Mass, urinary 5-HIAA, and serum lipids and stress from the mental conditions was not correlated directly to Serotonin, 5-HIAA, and serum lipids. I would like to conclude, therefore, that the detailed study should be performed on the function of serotonin of hypothalamus.