Homeopathy, (as opposed to allopathy,) is the system of therapy founded by Samuel Hahnemann (1755-1843), a German physician in 1842 based on the concept that disease can be treated with drugs (in minute doses) thought capable of producing the same symptoms in healthy people as the disease itself. A substance is used which creates the same symptoms as the disease or problem to enhance the body's natural immune and defense systems against the symptom and the problem. Homoios" in Greek means similar, "pathos" means suffering. For example, belladonna, a very potent poison in larger doses, causes headaches in very small doses and is used by homeopathic physicians in infinitesimal doses for certain headaches in certain patients. Homeopaths define the underlying principle for this matching process as the "law of similars." The "law" is not unknown to conventional (allopathic) medicine. Immunizations are based on the principle of similars. Modern allergy treatment, likewise, utilizes the homeopathic approach by the use of small doses of allergens in order to create an antibody response. Conventional medicine also uses homeopathic-like therapy in choosing radiation to treat people with cancer (radiation causes cancer), digitalis for heart conditions (digitalis creates heart conditions), and ritalin for hyperactive children (ritalin is an amphetamine-like drug which normally causes hyperactivity). Other examples are the use of nitroglycerine for heart conditions*, gold salts for arthritic conditions, and colchicine for gout. In classical homeopathy, treatments are designed and prescribed for each individual patient. One patient with a headache may receive a different medicine than another patient with a seemingly similar headache (to a non-homeopathic physician). Homeopathy's law of similars and its reliance on individual treatment can be readily understood and accepted by most people. Homeopathy's special pharmaceutical process is, however, its most controversial aspect. This process is called "potentization" and refers to a specific procedure of serial dilution, wherein one part of a medicinal substance is diluted with 99 parts distilled water or ethyl alcohol which then is vigorously shaken. One part of this solution is diluted further with 99 parts distilled water or ethyl alcohol and then shaken again. This process of dilution with shaking may be continued to different strengths, most commonly repeated 3, 6, 9, 12, 30, 200, 1,000, 10,000, 50,000 or 100,000 times. Homeopathic medicines are often so diluted that molecules of the active substance can no longer be found in the medicine. Homeopathic physicians believe the pattern or vibration of the substance remains and creates the reaction. Homeopathy was more popular in the United States around 1900 than it is today and today, it is more popular in Europe and India than the US.