Small amounts of cocaine produced the same type of effects the ancient South American people experienced when they chewed coca leaves. Sigmund Freud described those effects in his July, 1884 paper Uber Coca:

Exhilaration and lasting euphoria, which in no way differs from the normal euphoria of the healthy person...you perceive an increase of self-control and possess more vitality and capacity for work. In other words, you are simply normal, and it is soon hard to believe that you are under the influence of any drug.... Long intensive mental or physical work is performed without any fatigue.... This result is enjoyed without any of the unpleasant aftereffects that follow exhilaration brought about by alcohol.... Absolutely no craving for the further use of cocaine appears after the first, or even repeated, taking of the drug; one feels rather a certain curious aversion to it. (Byck, 1974:48).

Freud even recommended cocaine as a treatment for dangerous addictions to drugs such as morphine. But that was before the hypodermic needle was widely used and before Freud nursed someone through a cocaine-induced psychosis. After that, he withdrew his paper and his recommendations.