Sarcosine is the N-methyl derivative of glycine. It can be metabolized to the glycine through sarcosine dehydrogenase. It can be naturally found in many body tissues including muscles. In the laboratory, sarcosine could be synthesized through the reaction between chloroacetic acid and methyla mine. Sarcosine is a potential interesting direction for the treatment of mental illness such as schizophrenia, possibly being related to its effect of increasing the glycine content in the brain, which increased the NMDA receptor activity. Sarcosine is also effective in the treatment of depression. Recent study has shown that sarcosine might be an important bio-marker for prostate cancer.