Fecal Microbiota Transplantation for Patients With Autism Spectrum Disorder.

Inclusion Criteria: * Diagnosed by a child psychiatrist in line with DSM-5 Autism Spectrum Disorder * Combined with gastrointestinal problems, any Gastrointestinal Symptoms Rating Scale score≧3. * Age is between 7-30. * Participants who are willing to participate in the study and sign the informed consent. Exclusion Criteria: * Cases where clinical assessment cannot cooperate with fecal microbiota transplantation and examination. * Cases requiring antibiotics within 3 months before or after acceptance because of their physiological condition. * Cases requiring long-term use of proton pump inhibitors due to their physiological conditions. * Severe physical diseases, such as acute gastrointestinal diseases, severe malnutrition or underweight, immunodeficiency diseases, severe allergies or autoimmune diseases, brain injuries or severe organic brain diseases, will affect the evaluation of treatment results. * Severe mental illness, such as schizophrenia, bipolar disorder, etc. * Those who used probiotics one month before the case may affect the intestinal flora. * Pregnancy. * Cases that cannot understand the content of this research. * Participants who are unwilling to participate in the study or refuse to sign the informed consent. * Participants who are not suitable to include in this study, evaluate by PI or Co-PI.