Before I knew anything about pepper spray, I sprayed an aggressive dog with 6% Mace brand spray. The dog backed out of range, and then came right back at me. This happened a few more times, with me either missing entirely or hitting the dog a bit behind the face. The owner, who could hear something happening but could not see us, called the dog back to him. The next time I saw that dog, it charged at me, I sprayed and completely missed, and the dog stopped charging. I suspect that the dog was made sufficiently uncomfortable the previous time not to want any more spray, but only after I had already left.