Why does animal testing happen?
British law says that any new drug used for medicine must be tested on at least two different types of live mammal. One of these must be a large non-rodent type animal.
This is to make sure the drug works and doesn't hurt you.
Animal testing has also sometimes been used for developing:
In some countries animals are also used to test beauty products. But this is not allowed in Britain any more.
Does it work?
Animal testing has helped to develop vaccines against diseases like measles, rabies and mumps.
Drugs to fight the effects of HIV and cancer rely on animal tests to find new treatments.
Operations on animals have helped to develop organ transplant and open-heart surgery techniques.
But, an animal's response to a drug can be different to a human's and the stress the animals experience in the lab can affect the test results.
Are there any alternatives?
In the UK laws protect all lab animals from cruelty during testing and all labs are inspected regularly to make sure that the tests are being carried out properly.
However, campaigners against animal testing say these controls have not stopped some scientists from abusing animals.
Are the animals hurt during testing?
Taking human tissue samples and testing the drugs on them in a test tube.
Carrying out experiments using computer models and programs.
Looking at large numbers of statistics.
Animal researchers say that it will be impossible to stop all animal tests.
But most scientists accept that it is extremely important to minimize the suffering of laboratory animals, and to use as few animals as possible.
How do I know which products have been tested on animals?
Some companies and shops offer products that have not been tested on animals. They often put information about this on their website. You can also write and ask the makers of your favorite products for more information.