Drinking too much alcohol could set off a chain reaction making the skin more vulnerable to cancer, scientists believe.
Ethanol is converted to acetaldehyde after being ingested. The compound that is formed could make the skin more sensitive to harmful UV light, a study has claimed.
However, drinkers may also relax in the sun without enough protective clothing or sun cream, the researchers acknowledged.
Researchers from the University of Milan looked at 16 different studies involving thousands of participants. They found that consuming one alcoholic drink or more per day increases the risk of skin cancer by a fifth.
And risk increased with alcohol intake. Those who drank the equivalent of a few strong beers were up to 55% more likely to develop melanoma than non or occasional drinkers.
Dr Eva Negri, one of the study authors told the BBC: "We know that in the presence of UV radiation, drinking alcohol can alter the body's immunocompetence, the ability to produce a normal immune response.
"This can lead to far greater cellular damage and subsequently cause skin cancers to form. This study aimed to quantify the extent to which the melanoma risk is increased with alcohol intake, and we hope that armed with this knowledge people can better protect themselves in the sun."
Sarah Williams of Cancer Research UK, said: "This study doesn't tell us for sure whether alcohol is a risk factor for melanoma. As the researchers themselves point out, the results could be due to sunlight exposure rather than alcohol. Research has clearly shown that most cases of melanoma are caused by overexposure to UV rays - you can reduce the risk by avoiding sunburn."