Animal should not be used for medical research in any situation but In the world there are many scientist which are working for the betterment for human being .there are many researches where scientist must have to check the medicine are anything which is made for the human use and scientist cannot use it directly to human because it may be dangerous for human so for test purpose scientist use the animal for fist try if medicine work good on animal then they test it on the human.
There are many example where scientist used animal to save lives of people like they tested many medicine use from venom for heart disease and thread was also discovered for surgery purpose which will not be need to extract from body its main function was that it will disappear automatically and it was tested first time on white rabbit. We have report that it worked well and rabbit recovered very fast so now mostly that thread is using in all over the world.
On the other hand there are many people who loves animal to much they never allow to use animal for medical research because some time animal may die so they love animal lot and against this statement. But in my opinion we have to use the animal instead of human because we are using the medicine to save the life of human but in world sometime scientist use human too which are declared dead from the court so scientist must allow the scientist to use animal foe the lives of human.