The goal of this observational study is tolearn the association of gut microflora with the onset of perianal abscesses. The main questions it aims to answer are:

Question 1: To understand the structure of rectal microbial community composition and its relationship with pathogenic bacteria in patients with perianal abscess.

Question 2: Understand the structure of rectal microbial community composition in healthy people.

Participants will be collected with rectal secretions and stool specimens.In addition, patients with perianal abscess should also collect pus samples.

Inclusion Criteria:

• Observation group: ① Age between 18-60 years, local resident of Xi'an; ② met the diagnostic criteria for perianal abscess and underwent surgical treatment in our hospital; ③ did not use antibiotics before treatment; ④ himself and his family members were willing to participate in this study and signed informed consent.

Control group: ① Age between 18-60 years, permanent residents in Xi'an; ② had no serious chronic disease, no abnormality in physical examination in the last 1 week; ③ did not use drugs that may affect intestinal flora in the last one month; ④ himself and his family members are willing to participate in the study and sign the informed consent.

Exclusion Criteria:

• Failing to retain the specimens as required

Volunteers who did not keep the specimens as required