DSM-V diagnosed of GAD
Adults between 18 and 65 years old
Willing to participate.
Having illness including liver disease and kidney disease, diabetes, immune deficiency, etc
Having psychological illnesses including psychosis, Suicidal ideation, bipolar disorder and major depression
People who are expected to have limited partnerships such as forgetfulness and pregnancy
Taking any medication in the previous 1 month
Taking any medication related to psychiatric diseases including antidepressants, antipsychotics, etc. (maximum of two times per week) and antibiotics in the previous 1 month
Taking any supplement including probiotic supplement, fiber, prebiotics, omega-3, vitamins and minerals in the previous 1 month; Consumption of fermented foods (except yogurt), such as sour cream, acidophilus milk, kefir and some cheeses such as blue vein cheese or Swiss cheese in the previous 1 month
The compliance less than 80%.