Staff from Zhangtongtai collects water from a local river for herbal paste manufacturing in Hangzhou at a ceremony to mark the opening of the herbal paste festival.

According to TCM theory, winter is the best season to consume tonics and herbal medicines for better health.

"The sales volume in our stores is over 20 percent higher than in the same period last year," said Li Bangliang, head of Zhangtongtai, a major TCM store in Hangzhou.

Herbal paste is a liquid medicine originally kept in pot. Though prohibitively expensive earlier, industrial production has now made the paste affordable for most ordinary people. It is good for both women and men of different ages.

To raise awareness about the herbal paste and popularize it even further, several major TCM museums in Hangzhou have held herbal paste festivals one after another.

Initiated six years ago by Fanghuichuntang, a restored TCM museum in Hangzhou, herbal paste festivals are held in the three most famous TCM museums of Huqingyutang, Fanghuichuntang and Zhangtongtai each year from early winter.

The emergence of herbal paste festivals has resulted from the boom in the TCM sector in China and the world as a whole.

"Nowadays, we offer services to more young consumers, some of whom are even teenagers," Li said.

Records referring to herbal paste, a classical TCM prescription, are found in such early testaments as the ancient medical classic Shennongbencaojing, one of China's earliest pharmaceutical works. It became popular in the Tang Dynasty (618AD-907AD) and reached its peak in the Qing Dynasty (1644-1911). Known as a court-style pharmaceutical product in the beginning, herbal paste was meant only for emperors and rich people who could afford it. But now it is within the reach of a lot of common people.

Correctly employing the basic theory of TCM, herbal paste is developed under the premise that the human body is a unitary whole with a harmonious and complementary relationship between the internal and external, mental and physical.

"The doctors make prescriptions based on the combination of age, human environment, physique and symptoms of the patient," said Gao Guoqiang, pharmacist in charge of herbal pharmacy in Zhangtongtai.

First-class herbal paste requires excellence in every aspect, such as experienced doctors, authentic materials, a suitable pot, and precise working procedures. It is the result of a combination of doctor, pharmacy and procedure. It takes between eight and 10 hours to prepare the medicine to make a pot of herbal paste, of which quality of material, boiling time and storage procedure are very important aspects. Anything amiss at any stage will affect the quality of the herbal paste.

"The prescription we make is attached with a piece of paper on which warnings related to using the medicine and way of keeping fit are written," said Li Bangliang. "Herbal paste used to be stored in pots, but now it can be stored in small plastic bags thanks to new packaging technology."

With more than 200 years of history, Zhangtongtai enjoys public praise for its good quality. "We paid a visit to all the customers who used our herbal paste last year, and it turned out 90 percent reacted positively," Li said.