The invention relates to application of bifidobacterium lactis in prevention and treatment of mental disorder, the bifidobacterium lactis is bifidobacterium lactis BL-11, and the preservation number of the bifidobacterium lactis BL-11 is CGMCC (China General Microbiological Culture Collection Center) No.20847. The bifidobacterium lactis provided by the invention can be used for improving the intestinal permeability and reducing the levels of LPS and D-lactic acid in blood, so that the effect of preventing and treating mental disorders is achieved, and the mental disorders comprise anxiety, depression, attention deficit hyperactivity disorder, autism, autism, schizophrenia, hepatic encephalopathy, anorexia nervosa, Tourette disease and Escherberg syndrome.
Application of bifidobacterium lactis in prevention and treatment of mental disorder