The relationship between experience and reason has been one of the main topics in the history of philosophy. Experience and reasoning are the main ways through which human beings acquire knowledge. Experience and reason, however, have not always co-existed peacefully as is well shown in the antagonism between Empiricism and Rationalism in the 17th century European philosophy. Historically speaking, medicine has been the major source of empiricism. The Empiric School of the Hellenistic period claimed the superiority of experience over theory in justifying medical practice, which provoked a hot debate between empiricism and rationalism in medicine. The debate, which was philosophical by nature, has not received the due attention that it deserved. Again the problem of experience in medicine is fully discussed by a Swiss doctor and philosopher J. G. Zimmermann(1728-1795). He distinguished the true experience guided by proper reflections and the false experience which is the blind collection of simple facts. Based on this distinction, he admired Serapion, the founder of the Empiric School, as the possessor of the true experience, and criticized the empirics of his time who had been satisfied with false experience. This paper aims at clarifying the problem of experience in medicine by Zimmermann’s reevaluation of ancient Empiric School