The popular restaurant chain on Tuesday committed to removing antibiotics from its chicken wings by 2022. Pizza Hut said that the decision affects all the chicken wings it sells, including those in its WingStreet wings brand. The company has already removed antibiotics from the chicken it uses in its pizza.

In a statement, Pizza Hut was quick to issue a caveat: The promise relates only to antibiotics that are important to human medicine, a term used by the World Health Organization. It’s possible, therefore, that chicken wings from Pizza Hut could have other antibiotics in them that are not related in some way to human medicine.

Antibiotics have become an increasing concern worldwide. Scientists fear that as we consume more antibiotics—either byway of prescription medications given to us by doctors or in the food we eat—the bugs they’re meant to kill will become increasingly resistant. Eventually, experts fear, we could face powerful bacteria that we can’t kill with today’s antibiotics.

The problem, however, is that animals used for human food are often injected with antibiotics that have an effect on humans. And the more we eat those foods, the more antibiotics we’re getting into our systems, and the less likely we are to fend off threats.

In addition to its promise of removing human antibiotics from its chicken wings in four years, Pizza Hut said that it’s been working to remove other substances in its food. It’s already committed to removing artificial preservatives from its cheese and meats. In 2015, it removed artificial flavors and colors from its “core pizzas.”