Only Natural Pet Store Response:Flower Essence blends are finely tuned to very specific emotions in pets, and choosing the right fomula is sometimes a matter of trial and error. It is important to consider what is going on in your pet’s environment when you see a change in your pet’s behavior. A pet that becomes aggressive may have an underlying issue with fear or anxiety, or perhaps even a health issue that is causing him or her to become short-tempered. Also, Flower Essences used for behavioral issues typically work best along with some behavioral strategies. Particularly with dogs that start “acting out,” companions often need to use calm assertive communication to let the dog know who is in charge and what behavior is acceptable in your home and environment. We suggest that you consult with a qualified animal behaviorist if you are dealing with a serious behavior issue in your pet.