Among his students in Bonn were physiologist Nathan Zuntz (1847–1920) and chemist Hugo Paul Friedrich Schulz (1853–1932).
In 1868 he founded Archiv für die gesammte Physiologie des Menschen und der Thiere (now Pflügers Archiv: European Journal of Physiology), a publication that became the most influential journal of physiology in Germany.
He conducted research on intestinal peristalsis, the sensory functions of the spinal cord, the physiology of electrotonus, on protein metabolism and on regulation of body temperature by the nervous system, et al.
In one of his more important studies, he proved that respiration takes place in the peripheral tissue rather than in the blood.
He also performed extensive research of glycogen, and is credited with the creation of several physiological instruments.