The term homeopathy comes from the Greek words homeo, meaning similar, and pathos, meaning suffering or disease. Homeopathy seeks to stimulate the body's ability to heal itself by giving very small doses of highly diluted substances. This therapeutic method was developed by German physician Samuel Christian Hahnemann at the end of the 18th century. Hahnemann articulated two main principles:

The principle of similars (or "like cures like") states that a disease can be cured by a substance that produces similar symptoms in healthy people. This idea, which can be traced back to Hippocrates, was further developed by Hahnemann after he repeatedly ingested cinchona bark, a popular treatment for malaria, and found that he developed the symptoms of the disease. Hahnemann theorized that if a substance could cause disease symptoms in a healthy person, small amounts could cure a sick person who had similar symptoms. 

The principle of dilutions (or "law of minimum dose") states that the lower the dose of the medication, the greater its effectiveness. In homeopathy, substances are diluted in a stepwise fashion and shaken vigorously between each dilution. This process, referred to as "potentization," is believed to transmit some form of information or energy from the original substance to the final diluted remedy. Most homeopathic remedies are so dilute that no molecules of the healing substance remain; however, in homeopathy, it is believed that the substance has left its imprint or "essence," which stimulates the body to combat illness on its own and heal itself (this theory is called the "memory of water").