• Many animal models of disease are induced and cannot be compared to the human disease. For example, although genetic and toxin-mediated animal models are now widely used to model Parkinson's disease, the British anti-vivisection interest group BUAV argues that these models only superficially resemble the disease symptoms, without the same time course or cellular pathology.
• Some drugs have dangerous side-effects that were not predicted by animal models. Thalidomide is often used as an example of this, although the harmful effects of this drug are also seen in animals.
• Some drugs appear to have different effects on human and other species. Also certain human foods are poisonous to animals due to their body chemistry. Chocolate, onions, grapes, raisins, and Macadamia nuts are poisonous to dogs, while aspirin is poisonous to cats. If an animal dies from a new food product being tested, it doesn't mean that it is poisonous to humans.
• The conditions in which the tests are carried out may undermine the results, because of the stress the environment produces in the animals. BUAV argue that the laboratory environment and the experiments themselves are capable of affecting every organ and biochemical function in the body. "Noise, restraint, isolation, pain, psychological distress, overcrowding, regrouping, separation from mothers, sleeplessness, hyper sexuality, surgery and anesthesia can all increase mortality, contact sensitivity, tumor susceptibility and metastatic spread, as well as decrease viral resistance and immune response."
• Many household products and cosmetics companies still pump their products into animals' stomachs, rub them onto their skin, squirt them into their eyes, or force animals to inhale them as aerosol sprays. Charities such as the March of Dimes use donations from private citizens to fund experiments on animals, and the FDA requires all drugs to be tested on animals. However,...