Phenylalanine is an aromatic amino acid with physiological activity. It is one of the essential amino acids that the human body cannot synthesize naturally by itself. It is an important component of compound amino acid infusion; used in medicine, it is amino acids such as phenylalanine and sarcolysin formate. The intermediate of anti-cancer drugs is also the raw material for the production , thyroxin and melanin; existing studies have shown that L-phenylalanine can be used as a carrier of anti-cancer drugs to directly introduce drug molecules into the cancerous area, and its effect is 3 to 5 times that of other amino acids. This can not only inhibit the growth of cancer, but also reduce the side effects of drugs.