Rudolph August Witthaus (1846-1915) was an American toxicologist, born in New York City. He graduated from Columbia University in 1867, and from the medical department of New York University in 1875; studied in the Sorbonne and the College of France; and was professor of chemistry and toxicology at the universities of New York, Vermont, and Buffalo successively, and at Cornell (1898-1911). He acted as toxicological expert in several famous criminal cases. His publications include:
With T. C. Becker he also edited Medical Jurisprudence, Forensic Medicine, and Toxicology (second edition, four volumes, 1906-11), to which he contributed the introduction and volume iv.