With modern technology, there may be a way to limit the number of animals tested. A new substance, called a chemosynthetic liver, can mimic certain groups of enzymes found within the human liver. The liver can usually break down many drugs that enter a human body, preventing potentially harmful side effects. However, scientists and researchers must ensure that the drugs they are creating can be broken down.

This is where the animal test subjects come in. Scientists can track harmful byproducts of the drug inside an animal’s body, which can tell them whether or not they can move onto human testing. The problem is, new drugs can be extremely dangerous to the animals, causing the death of millions of mice.

Now, the chemosynthetic liver can replace the animals, and even speed up the usually slow decomposition process. Mukund Chorghade, the lead researcher at a company called Empiriko, told FoxNews that this new development won’t completely eliminate the need for animal testing.

Dating back to the time of the ancient Greeks, animals have been used to test various chemicals and drugs. While many animal rights activists have campaigned for decades to end this practice, an overwhelming majority of drug companies are still required to test on animals.

While a small percentage of animals live through this process, due to health and contamination risks, the majority of them are euthanized after fulfilling their purpose. Another sizable portion of these animals are killed as a result of the drugs or chemicals.

Fortunately, dogs, cats, and non-human primates make up less than one percent of the animals tested. Mice, guinea pigs, and rabbits are not as lucky. While mice and rats make up the majority of test animals, hamsters and farm animals such as pigs compile the remaining percentage.

“The data you get from animals is not 100 percent applicable to human beings, but one has to keep an important thing in mind— that animals are needed to understand mechanisms of disease,” Chorghade said.  “But any contribution we can make to minimizing animal testing — that is always something be lauded.”