Same prob with hartz ear mite drops. Rescued a stray here in NYC where I live. Had her 6 r 7 months, perfectly adjusted healthy rescue story. Noticed her scratching her ears n shaking her head a bit too much for normal. Checked her ears n sure nuff looked like coffee grinds in her ears, not bad but enough I knew it was likely ear mites. Bought hartz drops from local pet store. 5 drops in each ear. Poor thing wouldn’t sleep whole first night. Ears obviously red and very irritated. Vomiting. Diarrhea. Hiding n not herself. And all after only one dose. And I paid $7.49 here in NYC for those poison drops! Thank god caught it after 1 dose. Throw those things right in the trash….