More than 3.7 million scientific experiments were carried out on animals in the UK last year - an increase of 105,000.
Lots of people have really strong opinions about animal testing. Some think it's cruel, while others say it's vital to help develop medicines for humans.
But we want to know what you think...
Do you completely agree with it, do you think it's ok for some medical research but not for testing things like beauty products, or do you just think it's wrong, whatever the reason?
Whatever you think about it, let us know!
Sorry this page is now closed, but take a look below at some of the best comments.
"I think that animal testing is OK but only to test out new cures for diseases. I think it is wrong for testing cosmetic products."
"Ridiculous. Why harm a living creature that has feelings? It really angers me. Just because a cure is found by testing on animals, does that mean the cure will work on humans? Also, for lots of tests, there are actually alternatives available, so use them!"
"The only way to truly test drugs to see if they are safe is to test them on a living thing."
"I think it is really mean to test stuff like make-up on animals but if they test stuff that could prevent life threatening diseases I think it's a good idea. It is tight but I would rather a few mice die than a few humans."
"I think it is inhumane, the animals are suffering and there are many other ways to test medicines for human use."
"I think it is wrong to do tests on animals because animals are different to people and even if it works on animals it might not work on people!"
"How would YOU like it if you got tested on?! It is a terrible thing to do even if it is just a mouse. I've got a pet mouse and he is very nice and I could not bear to think of him being treated badly."
"Animal testing is bad and should not be done, not even for testing medicine. If they want to test medicine they should test it on themselves."
"I think it's right because it might kill a few animals but could save a few billion human lives!"
"I think that animal testing is disgusting, because the animals can't speak for themselves so they can't tell you if they are in pain. I think it should be banned."
"I think it is cruel to hurt animals while testing."
"I think it is cruel to test animals. Humans wouldn't like it if they were put in a box for experiments. I think animals are the same as people so they should be respected."
"It is really wrong."
"I think its disgusting that humans think it's OK to torture animals. Some say it is good because you then don't need to test all these medications on humans, but I don't see why animals are the victims."
"I think that animal testing is crucial for the growth of our economy and the advance of technology, but we have to make sure that the animal is in suitable conditions and that the best possible precautions have been taken."
"I think it's horrible, it puts animals through pain. It's plain wrong as we're not even similar to other animals. And would you like it to happen to you?"
"I think it's wrong, they're living things like us and it's as wrong as putting a human in a cage to be tested on!"
"I think testing anything on animals is wrong because it could hurt them and animals are just like people, they have feelings and should have more rights."
"I think it is okay, as long as it is to save the lives of humans! Although I do feel sorry for the animals."
"I think it's really cruel. If I were an animal that was being tested on I would hate it!"
"I think it's absolutely ridiculous to test on animals for things like make up, but if tests are humane and cause as little pain as possible, testing on animals for really important medical research has to be accepted or many people and animals could possibly die."
"It's completely right, I put human life above a mouse's. I know I'd rather test on a mouse than a human. Think of it this way, what if someone in your family died of a disease because there was no cure as we couldn't test it."
"I think it is a good idea because you can test things on animals to make medicines for humans, but I do not think it is OK to test make up and shampoo on animals."
"I think it's ok. If we never did testing then people would never get cured from severe illnesses. But on the other hand how would you feel if you were an animal and you got tested on? I would hate that so I'm on both sides."
"I think it's really cruel. People would never do that on humans, but for some reason it's OK on animals. I know what my cat Cinnamon would think of that."
"I think it's a good idea, because you can check animals for any illnesses and cure them, which prevents extinction."