That is not a fair test of homeopathy. Homeopathy claims that if the patient's complete symptom profile is taken, then a remedy that matches that profile will cure the patient of illness. It does not claim that it can invariably cope with acute poisoning, because the poison is also a drug, and you can't counter a drug homeopathically while it is still in action (this is one of the reasons that classical homeopaths are very adamant that you must ever only use one remedy at a time).
You can, however, often antidote a drug. But how this works is not entirely clear. It would seem that antidoting has mainly been invented to explain why remedies sometimes fail to have any effect.
Hans