Study Subjects: Eligible patients were initially diagnosed with chronic endometritis (CE) by CD138 testing through outpatient hysteroscopy. Positive CD138 expression is defined as at least one or more positive-staining plasma cells per 10 high-power fields identified as positive, and less than one positive-stained plasma cell identified as negative [8]. All patients signed an informed consent form prior to participating in the study, and the study followed the principles of the Declaration of Helsinki.

Inclusion Criteria: Diagnosis of chronic endometritis by CD138 immunohistochemistry; Age≥ 20 years old, females of childbearing age; Agree to undergo hysteroscopy and hysteroscopic endometrial biopsy; No serious systemic disease; There are no contraindications to oral administration of doxycycline hydrochloride and berberine hydrochloride.

Exclusion criteria: patients with pregnancy status, uterine malignant disease, hormone therapy within 3 months, glucose-6 phosphate dehydrogenase deficiency, hemolytic anemia, hypersensitivity to berberine hydrochloride or doxycycline. In addition, berberine hydrochloride has fewer oral adverse reactions, occasional nausea and vomiting, rash and drug fever, which disappear after stopping the drug. If the patient takes the wrong or missed medication, it is excluded.

Withdrawal criteria: If the patient has corresponding adverse reaction symptoms, those with mild symptoms can be temporarily observed, and if the symptoms are severe, they can be transferred to the Department of Gastroenterology for diagnosis and treatment, and those who need to stop the drug will be withdrawn from this study.

Grouping: The patients were randomly divided into the experimental group and the control group by a simple numerical table method, with a ratio of 1:1.

• Patients in the experimental group were treated with berberine hydrochloride tablets (0.1g*100 tablets/bottle, Shenyang First Pharmaceutical Co., Ltd., Northeast Pharmaceutical Group) + doxycycline hydrochloride capsules (100mg*24 tablets/box, Guangzhou Percello Pharmaceutical Co., Ltd.), with oral administration of berberine hydrochloride tablets 100mg Tid per day and oral administration of doxycycline hydrochloride capsules 100mg Bid per day for 14 days.
• Patients in the control group were treated with oral doxycycline hydrochloride capsules only and oral doxycycline hydrochloride capsules 100 mg twice a day for 14 days.

Evaluation indicators: Patients in both groups started taking antibiotics after being diagnosed with chronic endometritis by CD138 detection. After a course of treatment, the conversion rate of chronic endometritis expression from positive to negative was compared between the two groups.

Outcomes: Primary outcomes: Cure rate of chronic endometritis; Secondary outcomes: Number of CD138 positives per 10 high-power fields; Recurrence rate of uterine polyps, number and size of uterine polyps recurrence.

Inclusion Criteria:

Diagnosis of chronic endometritis by CD138 immunohistochemistry; Age≥ 20 years old, females of childbearing age; Agree to undergo hysteroscopy and hysteroscopic endometrial biopsy; No serious systemic disease; There are no contraindications to oral administration of doxycycline hydrochloride and berberine hydrochloride.

Exclusion Criteria:

Patients with pregnancy status, uterine malignant disease, hormone therapy within 3 months, glucose-6 phosphate dehydrogenase deficiency, hemolytic anemia, hypersensitivity to berberine hydrochloride or doxycycline. In addition, berberine hydrochloride has fewer oral adverse reactions, occasional nausea and vomiting, rash and drug fever, which disappear after stopping the drug. If the patient takes the wrong or missed medication, it is excluded.