Almost half a million people in 10 European countries were quizzed on their drinking habits as part of the EPIC* study which is funded by Cancer Research UK, the Medical Research Council and other European agencies.
The report, published online in the International Journal of Cancer, found that people who drink 15 grams of alcohol a day - equivalent to about two units - have about a 10 per cent increased risk of bowel cancer.
Those who drank more than 30 grams of alcohol - equivalent to three to four units which is less than a couple of pints of strong lager - increased their bowel cancer risk by around 25 per cent.
Professor Tim Key, Cancer Research UK epidemiologist and deputy director of the cancer epidemiology unit in Oxford, said: "The research shows quite clearly that the more alcohol you drink the greater your risk of bowel cancer.
The increase in risk is not large but it is important that people understand they can reduce their risk of a number of different cancers - including bowel cancer - by cutting down on alcohol."
Almost 480,000 people were asked questions about how much alcohol they drank and were followed up for six years. In that period 1833 people developed colon cancer.
Dr Lesley Walker, Cancer Research UK's director of cancer information, said: "There is a lot of confusion over safe levels of drinking. This partly arises over the increasing strength of some wines and beers and the fact that many pubs offer a large glass of wine that is actually equivalent to one third of a bottle.
"It is important that people do not automatically equate one drink with one unit. A large glass of wine with a high alcohol volume is likely to be the equivalent of considerably more than that.
"Cancer Research UK recommends that women should drink less than two units a day and men less than three.
"While there is increasing evidence that over indulging in alcohol can increase the risk of some cancers research also shows that by far the biggest risk for life threatening diseases is the combination of smoking together with drinking alcohol."
Source: Cancer Research UK