I found an interesting article for you from Time magazine about animal testing:

Dogs or other animals are used to test whether new products are safe and how well they work. In the case of makeup, I don't imagine animal testers are putting blush on a dog's cheek to see how good it looks. Instead, they might do something a little more horrifying like putting it in the dog's eye to see if it would be safe if that were to accidentally happen to a human.

There is one line from the article I mentioned above that I believe is absolutely true. It says, "It's everybody's hope [that one day we could replace animal trials entirely with computer modeling]."

Some people are adamantly against animal testing for any reason. I think it has to be unnecessary for makeup at this point and do appreciate the "no animal testing" notices I see on many cosmetics now. However, I do believe animal testing is still a necessary evil for testing new drugs. I know a woman who worked for a company that tested heart medications on dogs. Dogs were used because their cardiovascular system is apparently fairly close to that of humans (although the article I gave you says that pigs are more commonly used now and her studies would have been more than a decade ago.) The dogs she and her colleagues used for testing were dogs who were already going to be put to sleep by an animal shelter. Instead (I think this is what they did -- she told me about it a few years ago) they were given some sort of anesthesia, the scientists stopped their hearts deliberately and gave them a medication before attempting to start their hearts again. The dogs were put to sleep at the end of the procedure. As a dog lover myself, I have a very hard time saying that this kind of testing is still necessary for some drugs and I definitely do hope life scientists can move toward more modeling techniques. Of course, even besides the animal testing, I also hope there will be fewer dogs put to sleep by animal shelters in the near future.