[YEA] The best way to treat heartworms on a dog is Sardines in the can. The one that has oil in it. In the past few years, I had 3 dogs with heartworms and this lady told me about the sardines in oil and I tried it and it works. When a dog starts to cough it means it has heartworms. I have to say when a dog gets heartworms, it does damage the heart, but with the sardines in oil the dog will live for a long time. What you do is give your dog some sardines to eat, if the dog don't like it, force it in mouth and make the dog eat it. Then get a syringe and get some of the oil and put it in mouth. This is if the dog don't like it. I had to do this to one of my dog and after a while she would eat it on her own. My other 2 dogs loved it. Do this once a week for 1 month. If the dog is still coughing then do it longer. If the dog is big then give it all, but if it is small then half of the can. It will kill the worms in the heart.