Johann Ludwig Hannemann (25 October 1640 – 25 October 1724) was a professor of medicine who famously opposed the idea of the circulation of the blood.
He studied the chemistry of phosphorus, gold, and hematite; wrote articles on metallurgy, botany, theology, and various medical topics.
He was an adherent of the views of the ancients and pre-Renaissance alchemists.
He trained his medical students according to the schools of Galen, Hippocrates, and Aristotle.
He was the doctoral advisor of Georg Gottlob Richter.