Dear Huzoor, in Islam, is it a sin to experiment on animals? Well, nothing is sinful if its benefits are more than its drawbacks and if it is not unjust. Now, it is a very strange, imbalanced society as I find in the West. They accept the slaughtering of animals alright, but they have objections against experimenting with them for the general benefit of mankind. In more cases, you can draw much more benefits out of experimenting with animals than by eating them, for instance, because there are peoples we know who do not eat flesh and their health is good and there are nations, wide nations in the world, huge nations who don’t eat flesh yet they live on vegetables and other such diets and we find them quite compatible in life.
But if you were not permitted to experiment on animals, there won’t be any answer to many diseases for which you have got now the answer and the humanity as such would suffer so much. For instance, now you don’t find any cases of smallpox anywhere in the world. While previously, smallpox was one of the main, I mean, scourge of the mankind. People died by millions and those who survived, survived an ugly existence, you know, very very painful and suffering and sometimes they were turned blind, sometimes their faces were so pocked that it was difficult for them to find a companion in life.
They were so repulsive and the very suffering of this disease was so much and man as such is much more sensitive to agony and pain than low animals which are less conscious of their existence. So, what is this sense of justice or sense of fair play with those people who object to this? To save large number of more sensitive animals from much greater suffering, if you sacrifice a few animals placed lower in the order of life, less conscious of things and which are made anyway subservient to man, there shouldn’t be any objection to it whatsoever.
Only what you are prohibited to do is that you are prohibited to cause any undue, unnecessary, unproductive suffering to any animal. This is why in Islam, although you are permitted to eat the flesh of animals, you are not permitted to maim them, you are not permitted to kill them in a way as would cause suffering, undue suffering to them.
So, this is the general teachings of Islam. Remember this principle again that for the sake of greater benefits of a larger number, you can sacrifice lower number to a smaller degree. Lesser beings can be sacrificed for the higher beings. Higher beings cannot be sacrificed for the sake of lesser beings.