Shanghai police have caught 36 people for producing and selling counterfeit traditional remedy ejiao, or donkey-skin gelatin.
More than 8,000 bootleg products worth 40 million yuan (6.3 million U.S. dollars) were seized, China Daily reported on Thursday.
The counterfeits, actually made with ox hide and edible gelatin, were fakes of those made by Dong'e Ejiao Co, China's top ejiao maker based in Shandong Province.
The Shanghai Municipal Food and Drug Administration received a report from Dong'e Ejiao in 2017 that some shops in Shanghai were suspected of selling fake products of the brand.
The administration sent an investigation team in tandem with police. The team bought products from the shops and identified them as fakes.
The team later found that the suspects took part in illegal production in rural Henan Province since August. They made the counterfeits using ox hide and edible gelatin with fake labels and packaging supplied from Guangdong Province.
On Dec. 7, police raided the illegal production sites in Henan and Guangdong and a site where products were stored, while detaining the suspects.
About 90 percent of the country's ejiao products are made in Shandong Province, which mainly imports donkey skin from Peru, Mexico and Egypt.
According to the Qianzhan Industry Research Institute, the production of China's ejiao manufacturers has grown from 3,200 tonnes in 2013 to 5,600 tonnes in 2016, with an annual growth of more than 20 percent.