I worked at a veterinarian clinic for several years.. When pets were for brought in for their monthly Heart Worm Treatment this Ivomec mixture is what was administered instead of them giving the Heart Guard and others they sold. You must mix this and dose at the proper ratio to administer to your dog. IT IS SAFE AND ECONOMICAL especially great if you have multiple dogs or large dog(s). .BUT YOU MUST ADMINISTER CORRECTLY. This is a good, safe economical way to treat and protect your dogs from Heart Worms. Collies and Collie Mix Breeds are more sensitive to this and other H.W. treatments so Administer a smaller dose to Collie breeds. The proper mixture/ ratio and dosing is as follows 1 part Ivomec to 9 parts neutral liquid for diluting ( vets. office uses Propelene Glycol, neutral tasteless mixer, you can buy it at most vets offices 8 ozs. is about $10.-$12.) or use canola oil or vegetable oil . Ivomec is an oily liquid so even mineral oil would be o.k. too. Dosing with Ivomec/Oil mixture is 1/2 cc per 10 lbs. I use an empty vial 5-10 cc size for mixing ( You could have your vet save an empty one or two for you and clean it out using the large gauge needle and some rubbing alcohol and or oil or just some hot water( use the large needle to clean out the vial that you will be using to mix the Ivomec) You can purchase large gauge needles at feed stores and 3cc syringes for smaller dogs and larger syringes for giant dogs , at Drs. Foster and Smith or at most pharmacies, etc., take the needle off that comes on syringe and discard. You will only be using the large gauge needle to make the mixture and to draw it into the syringe and then remove it. Give the correct dose ORALLY, with no needle attached 1 (one) time per month. Give slowly on tongue, in mouth, DO NOT SHOOT IT DOWN THEIR THROAT! It Is oil, you don't want them to aspirate( don't get oil in their lungs!) again 1/9 mixture, 1/2 cc per 10 lbs.