There is still yellow discharge 30 days after perianal abscess surgery, the possible causes are perianal abscess is not completely cured, the formation of anal fistula, secondary infection and so on. 1. Perianal abscess is not completely cured: 30 days after perianal abscess surgery due to the failure to completely cure the disease, resulting in local wounds 30 days later there is still yellow discharge. 2. Formation of anal fistula: due to perianal abscess rupture or surgical incision and drainage process left outside the mouth, resulting in the formation of anal fistula, purulent secretions from the mouth, so there will be a perianal abscess 30 days after surgery and yellow secretion. 3. secondary infection: postoperative care, improper dressing change, failure to maintain perianal cleanliness, resulting in secondary bacterial infection, so can cause perianal abscess 30 days after surgery and yellow discharge clinical manifestations. When there is yellow discharge 30 days after perianal abscess surgery, it is recommended that the patient go to the hospital for further examination to clarify the cause of the disease and give treatment under the guidance of professional doctors.