Treatment of Tension-type Headache by Zhixuan Analgesic Tablets

The goal of this clinical trial is to learn if Zhixuan Analgesic Tablet works to treat frequent episodic tension-type headache in adults aged 18-60 years. It will also learn about the safety of Zhixuan Analgesic Tablet. The main questions it aims to answer are: * Does Zhixuan Analgesic Tablet reduce the number of headache days compared with placebo within each 4-week interval during the 12-week treatment period? * What medical problems do participants have when taking Zhixuan Analgesic Tablet? Researchers will compare Zhixuan Analgesic Tablet (4 tablets per dose, 3 times per day) to a matching placebo (a look-alike tablet that contains no active drug) to see if Zhixuan Analgesic Tablet reduces overall headache burden - including headache days, the amount of acute analgesic medication needed, the duration and severity of headaches, and the impact of headache on daily life. Participants will: * Take Zhixuan Analgesic Tablet or a matching placebo 3 times per day for 12 weeks * Keep a headache diary to record headache days, headache duration and severity, and any acute analgesic medication used * Attend scheduled clinic visits for check-ups and safety monitoring * Complete the Headache Impact Test (HIT-6) and a global self-assessment of treatment effectiveness at the end of the treatment period