In the late 1920's, a conventionally-trained German physician, Hans-Heinrich Reckeweg, M.D. (1905-1985), began researching and experimenting with homeopathic remedies. He was initially drawn to homeopathy while in medical school when a homeopath cured his father of a serious kidney disease. He completed his medical degree, then went to Berlin to study with masters of homeopathy. Once he began treating patients with homeopathic remedies, Dr. Reckeweg noticed how quickly the patients required another remedy. This concerned him since he was closely following the guidelines of well-experienced homeopaths. In his practice he observed that many human diseases seemed to be caused by exposure to toxins, both of external and internal nature. He termed this principle "Homotoxicology"; in other words, the study of toxins to humans. The presence of such toxins was undeniable in view of the increasingly polluted environment and widespread damaging lifestyle choices.

Dr. Reckeweg expanded Homotoxicology into a medical theory with many innovative aspects. He elaborated a six-phase table of Homotoxicology, by which physicians can trace a patient's medical history and locate the present medical complaint. He described 'vicariation' of illnesses (i.e., improvement and deterioration) and codified a Great Defense System of Five Parts. His treatise on Homotoxicology was published in 1955.

Dr. Reckeweg obtained better results with combinations of homeopathic reme