Chinese physicians used several different methods to classify traditional Chinese herbs:

The earlier (Han through Tang eras) Ben Cao (Materia Medicae) began with a three-level categorization:

Low level -- drastic acting, toxic substances Middle level -- medicinal physiological effects High level -- health and spirit enhancement

During the neo-Confucian Song-Jin-Yuan era (10th to 12th Centuries), the theoratical framework from acupuncture theory (which was rooted in Confucian Han theory) was formally applied to herbal categorization (which was earlier more the domain of Daoist natural science). In particular, alignment with the Five Phases (Tastes) and the 12 channels (Meridians theory) came to be used after this period.