Homeopathy is a system of medicine to help you restore your natural good health. Based on the fact that all living organisms automatically try to bring themselves back into health (for example the way skin heals itself when cut, or you throw up after food poisoning) it is an holistic treatment that uses tiny doses of specially treated substances from the animal, vegetable and mineral kingdoms to create a catalyst to stimulate you to start to heal yourself. Some people use homeopathy as an alternative health care system (they only use homeopathy) and for others it is complementary (they use it alongside treatment from their doctor).
Although homeopathy is acknowledged as a system of medicine as far back as the Greeks, the father of modern homeopathy is Samuel Hahnemann. He invented the way we dilute and potentise remedies used today and outlined the way to find out what each remedy is capable of doing (call proving the remedy).