According to the current edition of Exotic Animal Formulary, pp 564-565: Oral dose every 30 days is 0.05mg/kg for heartworm prevention (Ref. Brown and Hillyer in Saunders Manual of Small Animal Practice 1994) 0.055mg/per ferret of Heartgard-use small cat dose for heartworm preventative (Same ref. listed) 0.4mg/kg orally or subq for ear mites and ticks, repeat in 14-28 days (Same ref. listed plus Rosenthal in Vet Clin North Am Small Anim Pract 1994) 0.5-1mg/kg in ears, repeat in 14 days. For ear mite treatment, half dose in each ear. (Ref. Brown and Hillyer plus Brown in Exotic Formulary-Ferret Drug Doses 1999). Sounds like a lot of variation to me, and I haven't trusted Ivermectin since my German Shepard died after getting an injection of this stuff for demodecosis back in 2005. Contrary to what someone else submitted, Revolution (Selamectin) does treat ticks in dogs. Revolution has also been proven safe in ferrets in a 2007 study of off-label use. I have shared this link with others, here it is for all http://www.jarvm.com/articles/Vol5Iss3/Beck%2087-96.pdf There has been some talk about Selamectin becoming refractive, I haven't personally found this to be true. I purchase the large dog size vials, transfer the medication to a Boston round and measure out doses with a 1mL syringe, and have done so for my dogs, cats and ferrets without adverse issues since 2006. Your mileage may vary. Bonnie Tormohlen Managing Director Northern Arizona Ferret Alliance & Rescue, Inc [Posted in FML 7803]