Penthorum Chinese Parsh, also known as Ganhuangcao is effective in treating hepatitis as it is capable of clearing heat and toxic, treating jaundice, dissipating dampness and promoting blood flow. Modern scientific researches had discovered: Penthorum Chinese Parsh has the capabilities of protecting liver, lowering transaminase levels, treating jaundice and detoxicating, which is effective in delaying the clinical symptoms of chronic hepatitis B and controlling further development of hepatitis. The formulation of Gansu granules through the extraction of Penthorum Chinese Parsh has been recorded in the Drug Standard of Ministry of Public Health of the People's Republic of China, TCM Preparation, Volume 13th and included in the Catalogue of National Essential Drugs.

Gulin County lies in the temperate zone and the subtropics region with a climate that belongs to a subtropics monsoon. It has deep mountain boundaries and has a sea elevation of 300 to 1843 meters. Its has an average yearly temperature of 17.6 degrees Celsius, precipitation of 700 to 800 millimeters and frost free period of more than 300 days. The unique geographical position and optimal climate promoted growth of many herbs, which is also an ideal environment for Ganhuangcao.