Hahnemman's success was wonderful, particularly with endemic and epidemic diseases, that homeopathy quickly spread throughout Europe and across to America. Dr Fredrick Harvey Foster Quinn introduced homeopathy into Great Britain in the late 1820's and in 1849 he founded the London Homeopathic Hospital.

Homeopathy was brought to America in 1825 and rapidly gained in popularity, partly due to the fact that the excesses of conventional medicine were especially extreme there, and partly due to the efforts of Constantine Hering. Hering developed the doctrine that symptoms always move in a particular way: from the surface to the interior, from the extremities to the upper part of the body, and from less vital to more vital organs. His "Laws of Cure" state that the cure must take place in the reverse order of the appearance of the symptoms (first in, last out).

Nearly as important as Hahnemann himself to the development and popularization of homeopathy was the American physician James Tyler Kent (1849 – 1921). His most important contribution may be his repertory, which is still widely used today.
Homeopathy reached its peak of popularity in America in the decades 1865–1885. In the 1930s the popularity of homeopathy began to wane, especially in Europe and the United States, partly due to advances in biology and conventional medicine, partly due to a decline in coherence in the homeopathic community and partly due to increasing influence of AMA on medical practice. Homeopathy experienced a renaissance in the 1970s that continues to this day. George Vithoulkas, who studied in India, where the homeopathic tradition had remained strong, was instrumental in resurrecting homeopathy in Europe.

With advent of computer technology, the ease with which large symptom databases can be used has brought about profound changes in the way homeopathy is practised. Today a large number of homeopaths use personal computers to sift through hundreds of thousands of pages of provings and case studies. The homeopathic repertorisation software have made practicing homeopathy much more easier.