The remedies stimulate the body to heal itself. For example, if someone is jumpy and irritable and cannot sleep at night, a “homeopathic” dose of coffee can help to calm the person so he or she can sleep.
Another example: if someone is suffering from a cold where the main symptoms are clear, runny discharge from the nose, watery eyes, and sneezing, it might be helpful to give homeopathic doses of a medicine which produces similar symptoms. In this case, homeopathically prepared onion, Allium cepa could be helpful, since it produces symptoms just like these, as anyone knows who has chopped an onion. Note that people with hay fever accompanied by watery eyes, nose and sneezing may also benefit from the Allium cepa. This is because the medical diagnosis is not the most important thing – it is the quality of the symptoms that is important.
Of course, if someone is suffering from a cold in which his head and nose are stuffed, his eyes are dry and itchy and has a deep chest cough, Allium cepa won’t help. A different medicine that has a record of producing dry eyes, stuffy nose, etc. has to be found.