In April 1884 Freud read of a German army doctor who had successfully employed cocaine as a means of increasing the energy and endurance of soldiers. He determined to obtain some for himself and try it as a treatment for other conditions—heart disease, nervous exhaustion and morphine addiction. It was little known at that time and the extensive ethical and methodological rules governing modern drug trials did not exist. (来源：EnglishCN英语博客基地)
Freud took some himself and was immediately impressed with the sense of well-being it engendered, without diminishing his capacity for work. Having read a report in the Detroit Medical Gazette concerning its value in the treatment of addictions his next step was to recommend the substance as a harmless substitute to his friend and colleague, Ernst von Fleischl-Marxow. Fleischl. Who had become a morphine addict following repeated therapeutic administrations for intractable neurological pain and was in desperate straits, took to cocaine with enthusiasm and was soon consuming it in large quantities.
Meanwhile Freud continued to extol the virtues of the drug, writing a review essay on the subject, taking it himself and pressing it upon his fiancee, friends as a panacea for all ills, He had gone overboard with enthusiasm, writing to Martha when he heard she had lost her appetite,“Woe to you, my Princess. When I come. I will kiss you quite red and fees you ‘till you are plump. And if you are forward you shall see who is the stronger, a gentle little girl who doesn’t eat enough or a big wild man who has cocaine in his body.’’
Among the people to whom Freud introduced cocaine was his colleague Carl Koller, a young doctor working in the department of ophthalmology. Freud published his essay in the July issue of the Centralblatt für Therapie, concluding it by drawing attention to the possible future uses of the drug as a local anaesthetic. Koller was impressed, thought it likely to be useful in eye operations and two months later tried it out , first on animals and then on his own eyes with complete success. He was quick to publish his findings, thus securing a place in world history as the discoverer of what turned out to be virtually the only medical use for the substance.
Freud had missed his chance, but worse was to follow. Fleischl’s temporary improvement on taking cocaine was short lived. Within a week his condition deteriorated, his pain became unbearable and he relapsed into morphine consumption. He now had not one addiction but two, taking cocaine in doses a hundred times larger than Freud used to do. He suffered toxic confusional states in which he became agitated, experiencing severe anxiety and visual hallucinations. Yet Freud continued to advocate the use of cocaine in morphinism, presumably on the basis that (as had been reported by others) it was beneficial in selected cases.
His paper On the General Effect of Cocaine. Written in the spring of 1885, was published in August and subsequently abstracted in the Lancer, By the following year, however, cases of cocaine addiction and intoxication were being reported from all over the world. Freud came under severe criticism for his advocacy of the drug and defended himself by claiming(inaccurately)that he had never advised its use in subcutaneous injections. He expressed the following view, “Theory is fine but it doesn’t stop facts from existing.” This became a favorite warning against the uncritical acceptance of received wisdom.