In 2014, CVS Pharmacy stopped selling cigarettes because it conflicted with their "purpose of helping people on their path to better health."

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Comparing sales from from the months before and after the ban in 13 states, researchers determined that the pharmacy's decision seems to have paid, Reuters reports.

According to a study funded by the nationwide pharmacy chain, cigarette sales were reduced by one percent — that's 95 million packs — since 2104, in the thirteen states that were studied.

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Though one percent might not sound like a lot, it's definitely statistically significant. "It was a big enough effect that you could see it in the population level, which is very impressive," Stanton Glantz, director of the Center for Tobacco Control Research and Education at the University of California, San Francisco told Reuters.

According to the study, smokers who were exclusive customers of CVS were 38 percent less likely to buy cigarettes elsewhere once the ban went into effect. While the study cannot confirm that these smokers actually kicked the habit, the study does confirm that states where CVS pulled out of the tobacco market sold 0.14 packs per smoker fewer than other states.

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It was nearly 50 years after the American Pharmaceutical Association recommended that pharmacies stop selling cigarettes that CVS elected to pull the product from all of its 7,800 stores. Until CVS took action, no major pharmacy chain had implemented a ban.

In a video statement from the time, CVS CEO Larry J. Merlo said, "Tobacco products have no place in a setting where healthcare is delivered."

Upon announcing the change, CVS predicted they'd lose about $2 billion in sales, and in 2015 their stock dropped by about 3 percent. But according to CNN, that's all part of the gamble. As Matt Egan writes, "CVS is clearly betting the move will improve its brand image, especially among the growing population of Americans who don't smoke."

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Do other pharmacies still sell cigarettes?

Yes, according to Truth Initiative, a non-profit dedicated to ending cigarette use. They cite Walgreens, Rite-Aid, and Walmart as major pharmacies which still sell tobacco products. However, shareholders have recently been pressuring Walgreens to follow CVS' model and pull cigarettes from their shelves. And Walgreens might be buying Rite-Aid.

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Several municipalities have also outlawed pharmacies selling cigarettes, most notably in California and Massachusetts, but it is far from the law of the land.

It remains to be seen if other brands will follow suit, or if legislative action will mandate a change. But one thing is clear: what CVS is doing seems to be working.