Homeopathy literally means 'similar suffering' from the Greek words Homos and Pathos. It is based on the principle that like cures like.
For example, Coffee in its natural form can cause a person to experience headaches, sleeplessness and general feeling of all your senses being more acute. A Homeopathic preparation of coffea will aid in relieving those very symptoms, even if they are not caused by drinking coffee.
The burning and tearing of the eyes and the watery runny nose caused by a cold can be relieved by the remedy Allium Cepa, as they are similar to the symptoms you may experience from cutting into a red onion (Allium Cepa).
While simple remedies like these can provide quick and profound symptomatic relief, more complex remedies are used to address a patients' individual constitution. This is a Holistic approach.
Homeopathic remedies are regulated by the US Food and Drug Administration (FDA).

FAQ's about Homeopathy   

Partial List- Homeopathic Research