Drinking spirits rather than wine or beer is linked to an increased risk of inflammation of the pancreas, according to a new study.
Acute pancreatitis is uncommon but people with gallstones and heavy drinkers are more likely to develop the condition.
Overall, between 1% and 3% of heavy drinkers (more than four or five drinks a day) will develop the condition over 10 to 20 years.
Nevertheless, acute pancreatitis accounts for 25,000 hospital admissions and 950 deaths in England every year.
Previous research has shown that the risk goes up the more people drink but experts have not known which type of alcohol creates the most problems.
Now, researchers from the Karolinska Institute in Sweden have found that spirits increase the risk of developing acute pancreatitis, and just one large drink can have an effect.
Writing in the British Journal of Surgery, a team analysed decade-long data for 84,601 people aged 46 to 84, of which 513 developed acute pancreatitis.
The results showed that one drink containing 12g of alcohol (just under a double UK pub measure of spirits) increased the risk by just under 10%.
Meanwhile, consuming 60g of alcohol in one sitting (7.5 standard UK pub measures of spirits) increased the risk by 52%.
There was no increased risk from wine or beer.
The experts believe something in spirits could be causing a problem for drinkers.
"When alcohol metabolises it induces oxidative stress and this in turn can lead to damaged pancreatic tissue," said lead author Dr Omid Sadr-Azodi.
"However research has shown that alcohol on its own is not sufficient to cause acute pancreatitis.
"Our study suggests that there are constituents in spirits that are not present in wine and beer and that they can cause acute pancreatitis, either on their own or in combination with alcohol."
Dr Sadr-Azodi said the study showed a "steady increase between each measure of spirits a person drank on one occasion and the risk of having an acute attack of pancreatitis".
But drinking more than 60g of alcohol on one occasion did not increase the risk.
"We also discovered that the average monthly consumption of alcohol did not increase the risk.
"However, it is important to point out that most of the people included in our study drank alcohol within acceptable ranges, consuming one to two glasses a day."
The authors began investigating the different types of alcohol after figures showed a drop in the number of people with acute pancreatitis in Sweden when spirits sales declined, despite an increase in sales of wine and beer. A similar pattern occurred in Finland.