Animal experimentation is a process also known as vivisection, that means "killed while it was alive", it attempts to "recreate human diseases in animals in order to study them" (Levin, 1995). According to many scientists who practice animal experimentation, it is a scientific process that gives answers to the human needs in the world. Between the uses of the animal experimentation are the treatments for cancer, Alzheimer's disease, AIDS, heart diseases, also the discovery of vaccines, and antibiotics and many more. Pro – vivisection scientists assure that if "human beings had chosen to stop using animals in scientific and biomedical research, the world would be a very different place today"; besides, they defend themselves by saying that there are a lot of diseases that have been controlled through the knowledge obtained from vivisection; however, there has been an "enormous damage to the human health" caused by vivisection along with a lot of false claims (Klepacz, 2002). Consequently, animal experimentation does not apply to humans, has hidden side effects and has extremely high costs.
             The results of AIDS, cancer and heart disease test done on animals do not apply to the human beings for many reasons. First, it is known that researchers have been "infecting chimps with the HIV virus since 1984", but there are a lot of "dramatic" differences between "the chimpanzees and the human immune system" that points the "impracticality of using these animals as a model of human AIDS. Also some authors have noted that the stress associated with captivity can alter enzyme levels, thus invalidating experimental data" (PCRM, 2002). Second, rats are being used to test the causes of cancer in humans although they differ in many ways. In fact, rats are "poor predictors" of the human cancer risk because they are susceptible to different t...