Researchers from Queen Mary University of London (QMUL) reviewed all the available evidence from many studies and clinical trials assessing both the benefits and harms of preventive use of aspirin.
The researchers, led by Professor Jack Cuzick, Head of QMUL's Centre for Cancer Prevention, found taking aspirin for 10 years could cut bowel cancer cases by around 35 per cent and deaths by 40 per cent.
Rates of oesophageal and stomach cancers were cut by 30 per cent and deaths from these cancers by 35-50 per cent.
No benefit was seen whilst taking aspirin for the first three years, and death rates were only reduced after five years.
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However, the research also warns taking aspirin long-term increases the risk of bleeding from the digestive tract, eg stomach bleeding.
Amongst 60-year-old individuals who take daily aspirin for 10 years, the risk of digestive tract bleeds increases from 2.2 per cent to 3.6 per cent, and this could be life-threatening in a very small proportion (less than 5 per cent) of people.
"It has long been known that aspirin - one of the cheapest and most common drugs on the market - can protect against certain types of cancer," said Cuzick.
"But until our study, where we analysed all the available evidence, it was unclear whether the pros of taking aspirin outweighed the cons.
"Whilst there are some serious side effects that can't be ignored, taking aspirin daily looks to be the most important thing we can do to reduce cancer after stopping smoking and reducing obesity, and will probably be much easier to implement.
"The total number of deaths from any cause would also be lower, by about 4 per cent over a 20-year period. The benefits of aspirin use would be most visible in the reduction in deaths due to cancer," he said.
The study is published in the journal Annals of Oncology.