For several years now, scientists have been gathering evidence about the strange and surprising ways that common painkillers affect our emotions and behaviors. Here’s a new one to add to the list: Acetaminophen, the active ingredient in Tylenol, dampens your ability to empathize with the physical and emotional pain of others, new research in Social Cognitive and Affective Neuroscience has found.

For the study, participants were asked to rate the pain of someone described in a fake scenario who, say, cut himself with a knife or lost a parent. Those “on” acetaminophen, rather than a placebo, rated the pain lower. A separate experiment asked a participant to rate the hurt feelings of someone who had been excluded from a social game. The effect was the same.

“Empathy is important,” senior author Baldwin Way said in a statement. “If you are having an argument with your spouse and you just took acetaminophen, this research suggests you might be less understanding of what you did to hurt your spouse’s feelings.”

Earlier research has suggested that acetaminophen dampens both positive and negative emotions, and can make you more likely to make errors in decision making.

It’s hard to say at this point what the real social consequences of these effects might be, but the potential is staggering. Acetaminophen is the most common drug ingredient in the United States, and nearly a quarter of American adults take a medication containing it every week, according to the Consumer Healthcare Products Association.

That’s a lot of people who regularly have their empathic capabilities smothered. It’s a pretty big stretch given the evidence to date to say that the world would be a more caring place without Tylenol — it’s hard to play nice when you have a literal pain in the neck, too — but it’s worth noting that even common medications can affect your brain in complicated largely unknown ways. If at all possible, it would be wise to go find a professional who can get to the root of your neck pain, forgo the painkillers, and give your spouse a hug.

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