Daily, long-term doses of aspirin can slash the risk of cancer of the digestive tract, according to an overview of research published on Wednesday.

Aspirin greatly reduces the risk of developing and dying from bowel, stomach and oesophageal cancer, its authors said.

They found that taking aspirin for 10 years could cut bowel cancer cases by around 35 percent and deaths by 40 percent.

Rates of oesophageal and stomach cancers were cut by 30 percent and deaths from these cancers by 35 to 50 percent.

To gain these benefits, people had to start taking a daily dose of 75 to 100mg for at least five years and probably 10 years between the ages of 50 and 65.

No benefit was seen while they took aspirin for the first three years, and death rates were reduced only after five years.

Aspirin has long been considered to be a boost in the fight against cardiovascular disease and has also been investigated for reputed anticancer effects.

The new research is the first broad evidence that it can be a shield against these types of cancer, the scientists said.

The study, published in the European cancer journal Annals of Oncology, was led by Jack Cuzick, a professor at the Centre for Cancer Prevention at Queen Mary University of London.

It looked at more than 200 clinical trials and other studies that explored aspirin's anti-cancer effects.