Several hundred doctors and nurses jammed the courtyard of the No. 1 People's Hospital in Wenling, a city with a population of about 1 million in Zhejiang province, a four-hour train ride south of Shanghai.
They wore surgical masks to hide their identities from the government and waved white signs that read, "Zero tolerance for violence."
"Doctors and nurses must be safe to take care of people's health!" video shows them chanting.
The medical workers were reacting to a triple stabbing at the hospital three days earlier.