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My dog is suddenly aggressive towards me. What could be wrong?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Female | unspayed | 3 years old

My dog has been having sudden and unpredictable mood changes where she gets aggressive towards me. They don't last long and don't happen often or on a regular basis. Could someone help me figure out what this might be?

1 Answer

Most Helpful Answer

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Answered By Jennifer Summerfield, DVM CPDT-KA

Veterinarian, Certified Dog Trainer

Published on January 18th, 2017

I'm sorry to hear that you're having this problem! If this has been a fairly sudden behavior change for Elsa, the first thing I would suggest would be to have her examined by a vet to see if there may be a medial reason for the aggression - many illnesses including thyroid problems and neurologic issues can cause sudden mood swings and behavior changes like this, as well as anything that may be painful such as an injury of some kind, arthritis, etc. If your vet determines that Elsa is healthy, then I would strongly recommend making an appointment with a veterinary behaviorist as the next step. Aggression towards humans is a serious and complex behavior issue that needs to be handled by a professional who can work with your dog in person. The behaviorist will evaluate your dog and help you determine what is triggering the aggression, then put together a detailed training plan to work on the problem. You can search for a board-certified veterinary behaviorist in your area here: www.dacvb.org

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