Homeopathy is a different kind of medicine where "like cures like", in other words a disease can be cured by a substance that produces similar symptoms in healthly people. For example, if the symptoms of a cold are similar to poisoning by mercury, then mercury would be your homeopathic remedy.
There is also a principle of dilutions which states that the lower the dose of medication the greater its effectiveness, things are diluted and shaken vigorously. Process is called potentization, most homeopathic remedies are so...