This article addresses the differences between the basic concepts of drug therapy in Chinese traditional medicine (CTM) and modern Western medicine. In ancient times, throughout the world, humans used plants as food and medicine. In Europe, chemistry developed rapidly after the influence of Paracelsus. Active principles were isolated from plants, and drugs were prepared in the salt form to use as medication. In China, several drugs isolated from plants have been prepared in the salt form in recent years, but herbal medication, developed in the ancient tradition, continued to be widely used in Chinese populations. Some theories such as the yin-yang theory and the five-element theory were commonly employed to explain the rationale for the use of CTM. In this review, hypertension and diabetes mellitus are used as examples to illustrate the applications of CTM. The notions of the “whole” and the use of “relative” rather than absolute are important concepts, which distinguish CTM from modern medicine.