It might well be. The trouble, though, is that homeopathic "remedies" are diluted so much that absolutely *none* of the original substance remains, rendering the question of its biological activity completely moot. They're basically pure water. Google is your friend here; if you search on "rhus tox" you will quickly discover that the normal homeopathic dose is "30X". More diligent Googling will show you the meaning of 30X as used by homeopaths: X means 10-to-1 dilution, and 30 means the dilution is repeated a total of 30 times.
Let's suppose for the sake of argument that the molecular weight of the supposed active ingredient is, say, 100. Thus one mole of the substance weighs
100 grams. The chemist Avodgadro showed, in the 16th century, that one mole of any substance contains 6 * 10^23 molecules of that substance. (Google "Avogadro's number", or look that up in any chemistry textbook, for a full explanation.) Now suppose we start out with a kilogram of the original substance. That means we have ten moles, or 10 * 6 * 10^23 = 6 * 10^24 molecules.Dilute that 10:1 one time, and retain a portion equal to the original volume. You now have 6 * 10^23 molecules of the original substance in that portion.
Do that twenty-three more times -- you have six molecules.
Do it one more time -- you have a 60% probability of having one molecule.
That's only 25 dilutions. We still have five to go before we've reached the "30X" level, and by the time we get there, it's guaranteed that it's so dilute, that any random sample, of equal volume to the original, drawn from the entire diluted batch has only 6 chances in a million of containing even ONE MOLECULE of the original substance.
It would surprise me greatly if that proved to be biologically active.