There are many reasons animal testing is negative, however, this writer finds these four arguments to be the most compelling. 
    First, animal testing is morally wrong.   Innocent animals are being killed and injured every year, in fact 115 million animals are killed each year in the U.S. as a result of animal testing. In addition, according to the United States Department of Agriculture 6% of all animals tested experience painful experiments that require suffering. Although this seems like a small number that means of the 115 million animals that died in the US, approximately 900,00 were in agonizing experiments. This does not even begin to cover the countless animals that were blinded, poisoned, and maimed for the sake of a cosmetic brand.
    Second, the conditions of animal testing are inhumane.  More often than not poor treatment and terrible living conditions are the norm in animal testing. In a lab at the Boys Town National Research Hospital in Nebraska, The People for The Ethical Treatment of Animals, PETA, investigated and found that when surgeries were botched, and they frequently were, rather than end the animals' suffering, pain killers and veterinary care were denied. In another case at the Buckshire Corporation, a Pennsylvania company that supplies animals to laboratories, PETA was informed of animal mistreatment by a former employee at the corporation. PETA went and discovered 42 chimpanzees crammed in cages in a windowless basement, and uncovered multiple cats that were not getting medical attention for serious respiratory diseases. Another poignant example occurred at Wright State University in Ohio where three nurses notified PETA of inhumane treatment towards the lab animals. After they were notified, PETA investigated and found that dogs and rabbits were suffering and dying in a scabies experiment. One of the saddest stories is of a baby stump tailed macaque monkey, Britches, who was subjected to cruelty in animal testing. Britches as an infant was separated from his mother and had his eyes sewn shut, with thick twine. With his eyes sewn shut, he was left alone in a steel cage. Britches desperate for some companionship would cling on and hug anything, but the most he was supplied with for attacment was a padded cylinder.   Fortunately, Britches was rescued and rehabilitated by the Animal Liberation Front.   
    A third argument against animal testing is that due to the mistreatment animals are subjected to, the results are inaccurate.  Not only are poor living conditions and abusive treatment inhumane, they also may also be inadvertently ruining many experiments by adversely affecting and contaminating the data. Neurotransmitters in the brain send out chemical signals to different cells. The chemical make up of these signals are dependent on the emotions the subject is feeling. Drugs effect these chemical signals by interfering or stimulating the neurotransmitters and therefore the reactions. Depending on the  mood of the subject the drugs are going to cause different reactions thus a stressed monkey becomes an inaccurate subject to experiment on.  Therefore animal testing can often lead to inaccurate and unreliable results.The stress that animals endure in labs can affect experiments, making the results meaning less.  
    Finally, it is important to understand that human bodies and brains are different from rats and rabbits. In 2004, the FDA reported that 92 out of every 100 drugs that tested successfully in animal testing trials, failed in human trials.  For example in London six volunteers were given small doses of TGN1412 as an experimental therapy for arthritis and multiple kinds of sclerosis. Before they were given the doses this had been given to mice, rats, rabbits, and monkeys, resulting in no obvious side effects. However within minutes, all six of the men were on the floor writhing in pain. The compound that was supposed to dampen the immune system, had instead super charged it releasing many unwanted chemicals into the mens bodies.  The unfortunate result was that  many of the men suffered permanent organ damage. 
    Over all animals testing can be destructive and is more often than not unnecessary. There are so many alternatives to these inhumane practices, it would be barbaric to continue.