When is the best time to drink herbal medicine to regulate menstruation is related to the patient’s personal constitution and menstrual condition, which usually varies from person to person, and it is recommended to take it according to medical advice. The main treatment principle is to treat the root cause and regulate menstruation. Generally, it is recommended to start taking oral Chinese medicine about 1 week before the onset of menstruation. However, due to the different types of evidence, the timing of regulation should be adjusted accordingly. If the patient has Qi and blood deficiency, spleen and kidney deficiency, it is usually recommended to adhere to the medication throughout the menstrual cycle. If the patient has Qi stagnation and blood stasis, or cold clotting, it is better to start taking herbs 1-2 weeks before menstruation. If the patient has a low menstrual flow with abdominal pain and cold discomfort during the period, it can be taken during the period. If the patient has a heavy menstrual flow, accompanied by abdominal holding pain and lumbago, it is recommended to take it before or after the end of menstruation and pay attention to minimize the use of blood-activating drugs. During the period of menstruation, patients should pay attention to rest, keep regular rest and relaxation, avoid staying up late and straining, and avoid eating cold, spicy and stimulating food.