A molecule is the smallest possible amount of any substance. Most homeopathic remedies contain less than one molecule of the original plant or chemical extract. Some people believe that homeopathic medicine works by stimulating the body's own natural defenses. However, the use of highly diluted substances has not been shown scientifically to work. If there is less than one molecule of a substance present, it means that no substance remains.
Homeopaths say it is electromagnetic waves of the active ingredient it once contained.
They say that vigorous shakings between each dilution make this memory possible. Another explanation, heard less often, is that all of the shaking and dilution activity releases the essence, or healing life force, of the original substance. Many advocates of homeopathy indicate that they do not know how it works, and that later research will unlock that mystery. First, liquids are not known to have memories according to mainstream science. Second, if liquids could contain trace memories of materials, they would contain trace memories of all the other substances removed by purification procedures during water recycling.