It is acceptable to experiment animals to develop products

To certain extent, some animals such as monkeys are similar to human biologically. Through testing products and medicines on them, producers would be able to find out the potential problems of their products. By overcoming these problems, a safe product is produced and thus fulfilling people's needs.

There is no reason to test these products on humans, as the results are unpredictable.

The answer is obvious.
Those medicines and products are for human, we have to make sure they're safe for us before we consume them and we achieve this by conducting experiment. An experiment means TRIAL AND ERROR. We need guinea pigs for experiments and we know that guinea pigs die in experiments. Human are simply selfish and they never ever sacrifice themselves. Animals that share similar structures and biological pathways with us become the best substitutes.
The idea is definitely unacceptable
yet ‘TO HAVE ANY OTHER ELSE TO DIE FOR THE SAKE OF HUMAN’, that's the benefit.

Hope this helps...

Our quality of life has been improved significantly by biological research that sometimes relies on the use of animals in controlled experiments. A generation or more of people has never known what it was like to be unable to swim in the summer for fear of contracting polio, to go blind or deaf because of infections, or to expect that any cancer diagnosis was a death sentence.

Animal-based research has helped provide cures and treatments in those case and many more. Biotechnology companies have depended on animal research to develop more than 160 drugs and vaccines approved by the U.S. Food and Drug Administration, according to the Biotechnology Industry Organization. Those discoveries have helped hundreds of millions of people worldwide and prevented incalculable human suffering.

In addition, BIO (Biotechnology Industry Organization) has reported, animal research has led to 111 USDA-approved biotech-derived veterinary biologics and vaccines that improve the health of livestock, poultry and companion animals. Biotech veterinary products to treat heartworm, arthritis, parasites, allergies and heart disease, as well as vaccines for rabies and feline HIV, are used daily by veterinarians. Biotechnology has improved the way veterinarians address animal health issues through the use of biotech vaccines and diagnostic kits and improved breeding programs that can help to eliminate hereditary diseases.

All of this has been accomplished amid an array of government regulation and researcher self-policing that has made examples of animal mistreatment rare. At UW-Madison, the All-Campus Animal Care and Use Committee functions as an oversight body for all animal use. Such institutional bodies are required by the U.S. Department of Agriculture and the federal Animal Welfare Act.

The USDA and National Institutes of Health regularly inspect research institutions to verify the well-being and care of animals. With very few exceptions that serve as rallying points for advocates, animals used in research do not suffer more pain or distress than animals outside the lab. In fact, lab animals often receive the best of care because of their value to researchers.

Today, animal research is predominantly research involving rodents and rabbits. At GlaxoSmithKline PLC’s London division, for example, only 5 percent of research and development involves animals – and 99 percent of those animals are mice, rats and rabbits. Protesters may flash disturbing images of monkeys screaming in pain, but primates aren’t at the core of most animal research today.

Computer modeling has reduced the amount of animal research. So has cell-based research. The use of animal embryonic stem cells in drug testing has dramatically improved the quality of such tests, and more quickly provided researchers with information about the safety and efficacy of drugs.

In the future, use of human embryonic stem cells in drug testing could further reduce the use of animals in testing. Perhaps it is time for animal-rights groups to redirect some of their energy to standing up for human stem cell research.

For now and well into the future, animal testing will be a part of scientific research. That research is being conducted safely and humanely by researchers who are a dedicated to finding cures for some of mankind’s worst diseases – as well as conditions that plague animals themselves. Don’t let rare cases of cruelty to research animals drive public opinion about a practice that helps humans and animals alike.