To evaluate the efficacy and safety of Honghua Xiaoyao tablets in the treatment of premenstrual syndrome, and the results were further analyzed and evaluated by target trial simulation (TTE) framework.

In this study, the patients in the exposed group were treated with Honghua Xiaoyao Tablets, which were provided by Jiangxi Puzheng Pharmaceutical Co., Ltd. The administration method of this drug was oral: 4 tablets each time, 3 times a day, for a continuous medication period of 3 months. Doctors were required to provide detailed guidance on medication use and record prescriptions; during follow-up visits, the remaining drugs should be checked to track patients' medication adherence.

The patients in the non-exposed group did not use Honghua Xiaoyao Tablets or other targeted drugs, and only received routine clinical observation. No drug intervention was applied to them after obtaining informed consent. However, they completed the follow-up plan as well as various efficacy and safety assessments simultaneously with the exposed group. If patients needed to withdraw from the study due to their condition during the study period (in accordance with the Management of Premenstrual Disorders: ACOG Clinical Practice Guideline No. 7, this applied when premenstrual dysphoric disorder (PMDD) or premenstrual syndrome (PMS) symptoms occurred during follow-up and the patient could not tolerate them), on the premise that the patient had given full informed consent, doctors could recommend first-line drugs such as selective serotonin reuptake inhibitors (SSRIs) for intervention and other treatment regimens in accordance with clinical standards. At the same time, the reasons for the patient's withdrawal and subsequent treatment status should be recorded in detail.

Time zero was defined as the start of the treatment period, i.e., when the doctor issued the prescription. Follow-up visits began at this point, with one follow-up visit conducted every month. The follow-up period covered the 3-month medication period and 1 month after drug discontinuation. This clinical observational study was scheduled to be completed within 2 years.

Inclusion Criteria:

1. Age:18-40 years old (both ends included);
2. According to the 8th edition of "Obstetrics and Gynecology" (2014), patients diagnosed with premenstrual syndrome;
3. In accordance with the TCM syndrome differentiation standard of liver depression and qi stagnation.

Exclusion Criteria:

1. those who were allergic to the ingredients and excipients of Honghua Xiaoyao tablet (exposure group);
2. In the non-exposed group, those receiving or planning to receive other targeted medications for PMS, such as serotonin reuptake inhibitors (SSRIs), hormones, etc.;
3. irregular menstrual cycle (menstrual cycle not within 28±7 days);
4. serious diseases of cardiovascular, cerebrovascular, hematopoietic system, liver and kidney, and malignant tumors;
5. pregnant or lactating women, or those who plan to become pregnant within 6 months;
6. patients with mental illness and alcohol or drug dependence; Patients with other complicated lesions were not eligible for this study.

The somatic symptoms included headache, abdominal distension, limb swelling, breast pain, and insufficient motor coordination. Mental symptoms included irritability, emotional instability, depression and anxiety, changes in sexual desire, physical fatigue, insomnia, and loss of appetite. Behavioral changes are characterized by inattention, accidents, criminality, and suicidal tendencies, and these symptoms disappear after menstruation. The diagnostic basis is that if the above physical, mental and behavioral changes occur repeatedly and periodically during the luteal phase and last for more than three menstrual cycles, premenstrual syndrome can be diagnosed.