The principle of similars is the cornerstone of homeopathy. It says that a substance that produces characteristic symptoms in healthy people will heal a sick person with similar symptoms.
It is an old idea known to Hippocrates and rediscovered by Samuel Hahnemann (1755-1853), a German physician, chemist, and researcher.
Hahnemann became curious about the healing effects of Peruvian bark, a treatment for malaria, and tested it on himself by taking repeated doses. He developed symptoms like those of malaria and hypothesized that the barkâ€™s ability to cure was related to its ability to produce symptoms similar to the disease. This was the beginning of Hahnemannâ€™s quest to find an alternative to the dangerous and ineffective treatment methods of the late eighteenth century.
Dr. Hahnemann left traditional medicine and began to experiment with the principle of similars. Over the next 20 years, he tested mineral, vegetable, and animal substances on himself and other healthy subjects and meticulously recorded the effects he observed. These drug provings became the foundation for his encyclopedia on drug effects, the Materia Medica, still used by homeopaths today to match remedies with physical and psychological symptoms in patients.