This work attempts to present the pathological changes in the chemistry of our bodies in a coherent manner. The author justifies this endeavor by noting that it is becoming increasingly difficult for physicians who are further removed from our field, as well as for the younger generation, to gain an overview of the relevant issues. Furthermore, a comprehensive presentation highlights the gaps in our knowledge more clearly and directs researchers' attention more intensely to them. However, the main reason is that an overview of the whole is essential for understanding detailed research. The presentation consistently refers back to the physiological basis and uses it as a starting point to explain the deviations caused by or resulting from the pathological process.