Hahnemann discovered three chronic miasms - psora, sycosis, and syphilis - which he believed were the root causes of most chronic disease. Psora, the itch disease, was by far the most widespread and contagious. Hahnemann detailed long lists of symptoms that could result from each miasm. He believed antipsoric remedies could cure the underlying psoric miasm in a patient. While Thuja was specific for sycosis and Mercurius for syphilis, psora required one of many potential antipsoric remedies from his materia medica based on the case symptoms. However, Hahnemann did not clearly explain whether