Alcohol was first classified as a group 1 carcinogen - meaning it is an agent known to cause cancer in humans - by the International Agency for Research on Cancer in the 1980s.
Murthy said evidence of the link between alcohol and cancer has strengthened over time and that for some cancers, such as those of the breast, mouth and throat, the risk starts to rise when people have one or fewer drinks a day.
The World Health Organisation issued guidance in 2022 saying there is no safe amount of alcohol consumption that does not affect health. In a statement in the medical journal The Lancet Public Health, the agency said the latest data indicated half of all cancers that could be attributed to alcohol were caused by light or moderate drinking, defined as the equivalent of less than one and a half litres of wine, three and a half litres of beer, or 450ml of spirits a week.
The surgeon-general said less than half of all Americans were aware drinking alcohol increases the risk of developing cancer. Awareness was far greater for the increased risk from radiation, tobacco and asbestos, the advisory said.
While many countries, including the US, require alcoholic drinks to be labelled with some health warnings, such as the risks of drinking for pregnant women, few specifically alert consumers to the increased risk of cancer.
Ireland and South Korea have put warnings about cancer on alcoholic drinks in recent years.
Alcohol can cause cancer by damaging DNA, increasing inflammation, or altering the levels of hormones such as oestrogen. It can also make it easier for other carcinogens such as tobacco smoke to be absorbed into the body.
Financial Times