Homeopathy is a system of alternative medicine developed in the late 1700s, based on the principle of "like cures like". This means that a substance that causes symptoms in a healthy person can be used in diluted form to treat similar symptoms in someone who is ill. Homeopathic remedies are made by diluting substances from plants, minerals, or animals. Practitioners believe that the more diluted a substance, the more potent it is, a concept known as the "law of infinitesimals