Australian cancer authorities are warning people to avoid drinking, saying new studies overturn earlier beliefs and tightening the links between alcohol and lethal tumours.
At the most, the Cancer Council said in its revised advice on alcohol, drinkers should have no more than an average of two standard drinks a day for men, and one for women.
The warning follows a council analysis published in the Medical Journal of Australia showing a higher incidence of alcohol-caused cancer than previously thought.
More than 5000 new cases each year were linked to long-term drinking.
Twenty-two per cent of breast cancer cases were linked to alcohol, and new evidence linked alcohol and bowel cancer in men.
"We have known for some time that alcohol is a major risk factor for breast cancer, but only by applying international data to Australian drinking patterns were we able to estimate that more than one in five cases here are linked to alcohol," council chief executive officer Professor Ian Olver, a co-author of the report, said.
"Factor in the new evidence on bowel cancer in men and the established links to cancers of the mouth, pharynx, larynx, oesophagus and liver, and alcohol is clearly one of the most carcinogenic products in common use."
Some studies have linked good health and moderate drinking - such as red wine's reported benefits for the heart - but the council said there was no evidence of a safe threshold of alcohol consumption for cancer, or that the risk varied with types of alcohol.
It said any level of alcohol consumption increased the risk of developing a related cancer, with the danger increasing in line with the level of consumption.
Convincing evidence now linked alcohol to increased risk of cancers of the mouth, pharynx, larynx, oesophagus, the bowel in men and breasts in women.
Research also strongly linked alcohol to bowel cancer in women and to liver cancer, with some evidence associating heavy drinking with a higher risk of prostate cancer.
The risk was increased by smoking, poor oral hygiene, and poor diet or self-medication leading to deficiencies of nutrients such as folate and vitamin B6, or excesses of others such as vitamin A/B-carotene.
The danger increased with the combination of substances used.
In combination, smoking and drinking had been estimated to cause more than 75 per cent of cancers of the upper aero-digestive tract in developed countries.
Alcohol could also contribute to weight gain - and greater body fat caused cancers of the oesophagus, pancreas, bowel, endometrium, kidney and, in post-menopausal women, the breast.
The council now wants greater awareness of the risks in a nation in which it says alcohol has played a dominant role in defining culture for more than 200 years.
Campaigns warning of the links have started in Western Australia and Victoria, but the council said more was needed.