Vivisection is probably the most controversial of all the animal rights issues. 'Vivisection' literally means the cutting apart of live animals though the term, in its broad sense, means the experimentation on live animals. Most experiments don't involve any cutting, but many of them cause the animals pain and distress.
Many of the experiments test new medicines which could be beneficial to humans, but many animals are killed in the process. Animal testing has been branded as unreliable by anti-vivisectionists, along with some doctors and researchers, as animals can react to chemicals and conditions in very different ways to humans. Should animals be harmed for the health of humans? Animals are also used to test new cosmetic ingredients - should we put animals in harms way so that we can look good?
Some of the cruellest animal experiments are tests like the Draize eye test , in which a substance is dripped into the open eye of an animal (usually a rabbit) and any reactions are observed. The LD100 test (Lethal Dose 100%) uses 60 to 100 animals, and determines how much of a chemical or medicine the animals need to ingest before they all die. The LD50 test is similar, except that the dose needed to kill half of the animals is determined. This then assists in deciding a safe dosage level for humans.
It may be very difficult to end animal experiments. There will always be occasional successes with new medicines brought about by vivisection, but there are many more failures. There are also many medical miracles that have come about without animal testing. Does the saving of hundreds of thousands of human lives justify the killing of billions of animals? How does this issue compare with the killing of animals for their meat?