According to the study published in the Annals of Internal Medicine, women who took low dose aspirin on alternate days for 18 years saw a 20 per cent drop in their risk of developing colon cancer.
Researchers looked at 39,876 women 45 and older who were enrolled in the Women's Health Study.
Participants all took a low dose pill of aspirin (100 mg) or a placebo every other day from when they were enrolled in the study until 2004.
They found that women who continued to take aspirin on their own after the end of the trial had the lowest risk for colon cancer.
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There were no other differences between the placebo and aspirin groups for other cancer types, overall cancer risk or death.
However, women who took aspirin were more likely to have gastrointestinal bleeding (8.3 per cent versus 7.3 per cent) and peptic ulcers (7.3 per cent verses 6.2 per cent).
The researchers, led by the department of medicine at Brigham and Women's Hospital and Harvard Medical School, pointed out that not all women enrolled in the Women's Health Study were followed up with, and that cases of gastrointestinal bleeding were only self-reported.
Dr Andrew Chan, programme director of the gastroenterology training programme at Massachusetts General Hospital in Boston, told CBSNews.Com that this study was especially important because it was a randomised clinical trial with very many subjects.
"It shows even more substantial evidence that there is a chemopreventative benefit for colon cancer," he said.
Chan, who was not involved in the study, emphasised however that observed side effects of gastrointestinal bleeding and peptic ulcers are widely known, and this may play a role in a patient's decision on whether or not they want to take the medication.