The possible side affects of aspirin must be examined before it can be widely used as a cancer prevention method, the charity Cancer Research UK has said.
A new study suggests people who take a daily dose of aspirin could significantly reduce their risk of cancer.
"Aspirin is showing promise in preventing certain types of cancer, but it's vital that we balance this with the complications it can cause - such as bleeding, stomach ulcers, or even strokes in some people," Dr Julie Sharp, head of health information at the charity said.
"Before aspirin can be recommended for cancer prevention some important questions need to be answered, including what is the best dose and how long people should take it for. And tests need to be developed to predict who is likely to have side effects."
More top news
Pregnant women who smoke are more likely to give up if they are given shopping vouchers, new research suggests.
Children are eating the equivalent of seven and a half chocolate fingers for breakfast, campaigners have warned.
Stephen Fry has suggested that the "the patter of tiny feet" may be on the agenda following his wedding to Elliot Spencer.