The Shanghai south-school e-jiao gradually fell apart because of its sticking to fresh donkey skin rather than salted one as the major ingredients. With the herds moving further away as China urbanized, it lost its steady supply of skins.
The final straw was the 1994 government policy that insisted on a set price for all e-jiao in the market.
"The price set for e-jiao barely covered the cost of qualified donkey skin for our production. There was no way we could continue," Yang says.
Moving production to Xinjiang earlier this year seems to have resolved part of the problem. With burros in plentiful, clean water and unpolluted land, Kashgar proved to be an ideal location for the raw materials. And with the machines-backed latest processing techniques, the south-school e-jiao was revived. But it was still an effort as the skilled workers of the 1990s have now passed their prime, and a new training regime had to be introduced.
The new-born e-jiao is already being used for gaofang (herbal paste) production in Shuguang Hospital. For a change, ordinary locals can afford the new south-school e-jiao.
Among the other Shanghai TCM treasures that have been revived are Liu Shen Wan (literally six-god pills), a secret patent drug of the Lei's Pharmacy that thrived during the Qing Dynasty (1644-1911). The drug, which is the same size as sesame, can be taken orally or applied externally and provides immediate relief for inflammation, such as pharyngitis, tonsillitis, scabies and boil.
A secret recipe that included precious ingredients like musk, bezoar and pearl, Liu Shen Wan, in its hey days, used to be more expensive than gold.
The Lei family revealed its secret recipe to the government in the 1950s, and Liu Shen Wan started being made at the Shanghai Traditional Chinese Medicine Pharmaceutical Factory in 1962, supported by modern technology. But the shortage of natural musk limited production.
In the 1970s, Gu Bohua, a famous TCM physician, created a new drug Liu Ying Wan for similar functions but with ordinary ingredients.
"Based on Lei's secret recipe and his own clinic experience, Gu replaced the musk with clove while adjusting the dosage of all the ingredients, which brought down the costs and making it affordable," says Xu Min, a clinical pharmacist at Yueyang Hospital attached to Shanghai University of TCM.
Physician Dai Ruihong attempted something similar with the recipes of three ancient patent drugs used for acute heart problem since the Song Dynasty (960-1279). He reworked the original recipe with seven carefully selected ingredients and created the sesame-sized Shexiang Baoxin Wan.
"The sesame-sized pill has proved valuable during heart attacks as it is easy to carry and takes effect within 30 seconds," says Xu.
The availability of artificial musk later made it more cost-effective as the treasures of Shanghai began to unravel for the ordinary people.
A bottle of Shexiang Baoxin Wan with 42 pills today costs about 40 yuan (US$5.88) while a box of Liu Shen Wan with 60 pills costs 50 yuan.
The arrival of an increasing number of TCM physicians from around China since the 19th century has granted Shanghai great advantage in TCM research and production, says Professor Qian of Shanghai University of TCM. "Of course, the development of Western medicine here is also encouraging local TCM physicians to innovate for the better."
"Production costs may continue to be an issue, but these treasures from Shanghai TCM will continue to shine in the market," Qian says.