Homoeopathic medicine came to light at the end of the 18th century, through the work of Samuel Hahnnemann, a German physician, chemist and scholar. He practiced medicine for a number of years in what now Germany, but gave up his medical practice because of its in-effectiveness. Most of medical practices then consisted of blood-letting (thee extraction of blood by cutting a vein or using leeches), based on the notion that most diseases were due to too much blood ; or the use of strong toxic substances such as mercury compounds ,that often left the patient in a state of profound anemia . Medicine, as we know it today, only began to exist in the 20th; century, and especially after the 1930’s when the use of Sulpha drugs and then antibiotics became common.
Hahnemann’s first comments about the general applicability of the law of similars in 1789 when he translated a book by William Cullen, one of the leading physicians of the era. At one point in the book Cullen ascribed the usefulness of Peruvian bark (Cinchona) in treating malaria due to its bitter and astringent properties. Hahnemann asserted that the efficacy of Peruvian bark must be for other factor, since he noted that there were other substances and mixtures of substances decidedly more bitter and more astringent than Peruvian bark that were not effective in treating malaria. He then described his own taking repeated doses of this herb until his body responded to its toxic dose with fever, chills, and other symptoms similar to malaria. Hahnemann concluded that the reason this herb was beneficial was because it caused symptoms similar to those of the disease it was treating.