Toxicity
From the earliest records regarding the use of medicinals to today, the toxicity of certain substances has been described in all Chinese materiae medicae. The toxicity in some cases could be confirmed by modern research (i.e., in scorpion); in some cases it couldn't (i.e., in curculigo).
Substances known to be potentially dangerous include aconite, secretions from the Asiatic toad, powdered centipede, the Chinese beetle (Mylabris phalerata, Ban mao), and certain fungi. Further, ingredients may have different names in different locales or in historical texts, and different preparations may have similar names for the same reason, which can create inconsistencies and confusion in the creation of medicinals, with the possible danger of poisoning.
Read more about this topic: Chinese Herbology