Alcohol is a pretty effective pain reliever, a new study spotted by The Independent finds—in some cases, better than some painkillers. New research in the Journal of Pain examined 18 different studies on pain and alcohol use with a total of more than 400 participants.

Researchers from the University of Greenwich in London found that for every drink consumed, participants reported a small reduced sensitivity to pain. But that effect added up: After three drinks for men and two drinks for women, the painkilling impact increased to “moderate-large.”

Drinking raised people’s pain thresholds a little, making them rate pain as less intense. For moderate pain levels, the researchers found that “analgesic [pain-relieving] effects of alcohol on pain intensity are comparable to opioids.”

In a comment to The Sun, lead researcher Trevor Thompson drew parallels between alcohol and traditional painkilling drugs. “It can be compared to opioid drugs such as codeine, and the effect is more powerful than paracetamol,” he said.

It’s not clear what effect alcohol has on the body that causes this pain relief. The researchers hypothesize that based on studies in mice, it may be that it blocks the transmission of pain signals in the spinal cord. But they also suggest alcohol’s anxiety-relieving properties may play a role.

Booze is cheap compared to prescription drugs, so it’s not really a good thing that it’s such an effective painkiller. To get the pain-relieving effects, you’d have to drink more than the 10–20 grams of ethanol that many international health organizations [PDF] recommend as your daily maximum. (A single 12-ounce beer has around 14 grams.)

Because alcohol makes people in pain feel good, there’s an incentive to keep using it. Eventually, you’ll need to drink more to get the same amount of pain relief, and you could become dependent on it. Being in chronic pain is bad for your health, but so is alcohol abuse, so in some cases, people might just be trading one problem for another.

[h/t The Independent]