While he was in medical school, Freud began to experiment with cocaine. He took it himself and insisted that his fiancée, sisters, and friends try it as well. He became enthusiastic about the substance, calling it a "miracle drug" and a "magical substance" that would cure many ills. He earned much notoriety as a result of his endorsement of cocaine in articles and lectures, but he later regretted his involvement when cocaine came to be recognized as addictive. For many years it was believed that, by 1887, Freud had stopped using cocaine himself. However, recently published letters from Freud to his friend Wilhelm Fliess reveal that Freud used the drug at least ten years longer, well into middle age (Freud, 1985).