Asked by user in California. Answered by Enjuris Editors.
I'm sorry this happened to you.
If you can prove that your landlord intentionally made your dog sick, you can sue them for damages (for example, veterinary expenses). You can learn more about lawsuits based on intentional torts here.
Additionally, if you believe your landlord is intentionally poisoning your dog, I would recommend contacting your local police department and reporting the incident. Your landlord may be held criminally responsible under California Penal Code 597.