People are lining up at hospitals across China to receive sanfutie plasters, a traditional Chinese remedy used during the dog days of summer, which began on Wednesday.

Sanfutie can help with conditions such as diarrhea and rheumatic arthritis, according to Zhang Shunan, head of TCM at the China-Japan Friendship Hospital in Beijing. The remedy was first recorded in Zhangshi Yitong, a book published in 1695.

The hottest part of summer, from July 12 to Aug 20, is known in China as Sanfu Days.