This is somewhat like causation in that the remedy needed is based on the actual substance that has produced the problem. It's also called using isopathic remedies, but isopathy goes a step further in using the diseased matter as a remedy.
I generally think of tautopathic as using the substance that caused the disease. It's using potentized chocolate for the kid who can't get enough chocolate or making up a remedy from the paint that the sick painter uses. Remember that this is not following the totality of symptoms rule and isn't considered classical homeopathy.