German pathologist who recognized the phagocytic (capable of engulfing bacteria and other substances) activity of certain cells found in diverse tissues and named them the reticuloendothelial system (1924). He also described (1904) the inflammatory nodule (called Aschoff's bodies, or nodules) in heart muscle characteristic of the rheumatic process.

Aschoff received his medical degree at the university in Bonn in 1889, and in 1906 he received an appointment to the chair of pathology at the university in Freiburg im Breisgau, where he spent the rest of his career. At Freiburg he established an institute of pathology that attracted students from all over the world.