While medicine is solidly grounded on scientific areas such as biology and chemistry, some argue that it is in its essence not a science at all. With medicine playing a substantial societal role, addressing questions about the scientific nature of medicine is of obvious urgency. This paper takes on such a task and starts by consulting the literature on the “demarcation” problem in the philosophy of science. Learning from failures of earlier approaches, it proposes that we adopt a Deflated Approach, (...) which acknowledges that “science” is a family resemblance concept that admits differences of degrees to nonscientific undertakings. Then, drawing on Paul Hoyningen-Huene’s ; account of systematicity and Alexander Bird’s analysis of examples from the history of medicine, the paper argues that medicine meets the requirement for systematicity on all dimensions and thereby qualifies as a science. The paper then considers and defuses two objections. First, it is shown that nonepistemic differences linked to the distinctive duality of medicine do not warrant thinking that medicine is not science. Second, against some recent criticism, the paper uses homeopathy as an example to show that systematicity can succeed as a demarcation criterion. (shrink)