Chaoye Qianzai 朝野僉載 by Zhang Zhuo 張鷟 (?658-730):
Hao Gongjing was collecting medicines on Mount Tai and passed by the market. Someone who saw spirits was shocked at how the flock of spirits would see Gongjing and all run away from him. After getting his medicine he mixed a “spirit slaughtering pill”. Any ill person who took it recovered.