Thirty-five restaurants across China have been busted for using poppy seed capsules in their cooking. Despite being classified as an illegal food in China, poppy seed capsules have been making frequent appearances in “traditional” Chinese cuisine as of late.

According to the National Food and Drug Inspection Bureau, the 35 restaurants have been accused of using poppy seed capsules or one of its variants such as papverine, morphine, codeine, noscapine, and thebaine.

Poppy seed capsules (shown above) are most frequently used in hot pot, noodle soups, and lobster sauce. In addition to its potentially addictive properties, the additive is said to make food “tastier”.

Shanghai restaurants and stores caught in the crackdown include Jiaxin Restaurant, Youqin Food Store, Dongjikai Restaurant, Shengxian Restaurant, the popular Zhouheiya franchise, and a Nanjing steamed bun eatery on Gulian Road in Jinshan District.

Beijing restaurants accused of using poppy seed capsules include Huda Restaurant; the Diannan Fuxi Eatery in Liangxiang, Fangxiang; Baoheju Restaurant in Dongcheng District; Rong Roast Chicken in Xicheng District; and the Zhenbao Restaurant chain. Other restaurants named in the crackdown include locations in Wenzhou, Zhejiang; Loudi, Hunan; and Weifang, Shandong.

In February 2014, a Foshan restaurant was raided after a number of men testing positive for morphine complained that they never used the drug, and suspected the food they ate at a local restaurant. A search of the restaurant’s kitchen discovered a bottle containing opium, morphine, poppy pods, and other illegal additives.

Poppy seeds are not uncommon in Guangdong or throughout parts of China, and had been traditionally used in dishes until recently banned. In Chongqing, it had been routinely used in hotpot dishes. Some mala tang (麻辣烫) and marinated foods also use poppy seedpods for extra flavors.