Just like people, it is possible for a dog to have an allergic reaction to something such as a bee sting, a medication, or a vaccine.
Lymphoma is a cancer of the immune system. The immune system is active throughout the whole body, and lymphoma can develop in any part of it. Symptoms vary depending on what type it is, where it is, and how aggressive it is.
Chocolate contains a substance called ‘theobromine’ which is toxic to dogs and cats. It’s similar to caffeine and can cause problems with the nervous system, bowels, kidneys and heart.