The use of monkeys and other animals used in experiments is being looked into by a group of top scientists.
It follows big rows between researchers and animal welfare groups over the need for new animal testing centres.
Around 3,000 monkeys are used in British labs each year, mostly for testing out drugs meant for humans.
But animal rights supporters say the tests aren't really useable because the results of the research applies to monkeys and not humans.
The review will look at possibly using computer data or other kinds of animals - for example, genetically modified mice - for some of the experiments.
But animal welfare groups want an end to the experiments altogether.
They argue that many of the tests cause needless suffering.
But researchers say that some monkey experiments have been "essential for developing new treatments".