Patients with schizophrenia frequently have difficulties in bowel habits due to medical adverse effects and unhealthy lifestyle, and the use of various interventions to ameliorate the problems have been noted in clinical setting. Probiotics including Kombucha tea have been proved to modulate the human gut microbiota which may help to improve the stool passage, and have been attracting the public attention across the world. However, little is known among the patients with schizophrenia. In the present study, the research team intends to evaluate effectiveness of Kombucha tea when used in the clinical settings.

• Inclusion Criteria:

  1. Inpatient patients diagnosed of schizophrenia according to DSM-5 criteria with the ICD-10-CM codes of F20.x. and hold the cards for Severe Illness issued by the National Health Insurance Administration, and
  2. Are currently and have been hospitalized at the psychiatric rehabilitation ward for more than 6 months, and
  3. Are at relatively stable psychiatric state and able to clearly express their perception or observed bowel conditions, and
  4. Are able to read or communicate with Mandarin or Taiwanese, and
  5. Are able to consent the agreements, and
  6. Subjectively experience difficulty in stool passage, such as decreased frequency, requiring medication or mechanic aids for defecating.

• Exclusion Criteria:

  1. Having an allergic history to fermented food, alcohol or other food, or 2. Severely impaired in cognitive performance, or 3. Having medications, antibiotics, probiotic or other fermented products that may influence gut microbiota at the time or within 3 months of the study, or 4. Having the illness that may affect stool passage or related with intestinal obstruction, such as severe gut disease, intestinal incarceration, tumor, inflammation, stenosis, or hemorrhoid, or 5. Having received major gastro-intestinal surgeries, or 6. Having the ongoing or history of medical illnesses, such as cancers, chronic obstructive pulmonary diseases, peripheral vascular diseases, autoimmune diseases, chronic kidney diseases, diseases involving abnormal metabolic function of visceral organs, or current infections, or 7. Participating other ongoing interventional research that may interfere the implementation or the results of present studies, or 8. Being obviously unable to comply with the execution of the study, or 10. Being declared of guardianship.