Inclusion Criteria:
* Adults aged 18 to 70 years.
* History of episodic migraine for at least 12 months before screening, meeting the International Classification of Headache Disorders, 3rd edition (ICHD-3) criteria, or clinically diagnosed migraine with no more appropriate ICHD-3 diagnosis.
* During the 28-day screening period, participants must meet criteria for episodic migraine, defined as headache occurring on \>=6 and \<=14 days, of which \>=4 days meet at least 1 of the following: (1) ICHD-3 criteria C and D for 1.1 migraine without aura; (2) ICHD-3 criteria B and C for 1.2 migraine with aura; (3) probable migraine (missing 1 migraine criterion); or (4) headache considered to be migraine based on a positive response to migraine-specific acute treatment (e.g., a triptan or an ergotamine derivative).
* Not receiving preventive migraine medication for at least 5 half-lives before enrollment, or receiving no more than 1 preventive migraine medication at a stable dose and regimen for at least 2 months before informed consent, whether for migraine or another medical condition (e.g., propranolol for hypertension).
* Body mass index (BMI) between 17.5 and 37.5 kg/m2, and body weight between 35 and 120 kg.
* Adequate compliance with headache diary completion during screening, defined as completion on at least 24 of 28 days (\>=85%), with diary data considered acceptable by the investigator.
* Able to comply with study restrictions and complete all protocol-required study procedures.
* Able to understand and sign the informed consent form.
* No major cardiovascular, hepatic, or renal disease.
Exclusion Criteria:
* Known allergy or hypersensitivity to Gou-Teng-San or any of its ingredients.
* Receipt of botulinum toxin type A injections in the head, face, or neck for any reason within 4 months before screening.
* Use of opioid-containing or barbiturate-containing medications on more than 4 days per month.
* Lack of efficacy after at least 3 months of treatment at accepted migraine treatment doses in 2 or more of the following preventive medication classes: (1) topiramate or valproic acid; (2) flunarizine; (3) amitriptyline, venlafaxine, or duloxetine; (4) atenolol or propranolol.
* Use of migraine treatment interventions within 2 months before screening, such as nerve block or transcranial magnetic stimulation.
* Clinically significant hematologic, cardiac, renal, endocrine, pulmonary, gastrointestinal, urinary, neurologic, hepatic, ophthalmologic, psychiatric, or other disease that, in the investigator's judgment, would interfere with study participation or study procedures.
* Participation in another clinical trial of a drug or medical device within 2 months before screening, or within 5 half-lives of the investigational product used in that trial, whichever is longer.
* Use of other Chinese herbal medicines within 4 weeks before screening.
* Previous exposure to monoclonal antibodies targeting the calcitonin gene-related peptide (CGRP) pathway or CGRP receptor antagonists.
* History of alcohol or drug abuse within the past 2 years.
* Women who are breastfeeding, have a positive pregnancy test at screening, or are unwilling to use contraception during the study if of childbearing potential.
* Any other condition or circumstance that, in the investigator's judgment, would make the participant unsuitable for the study or unlikely to complete the study successfully.
