Walgreens is planning potentially sweeping store closures as it faces what its CEO called a “challenging” environment for pharmacies and U.S. consumers.

The pharmacy chain on Thursday morning announced quarterly earnings that fell short of Wall Street expectations. Walgreens’ stock dropped more than 20% just minutes into the trading day.

In an interview with CNBC, CEO Tim Wentworth said the company now forecasts weaker consumer spending for the rest of the year.

″We assumed…in the second half that the consumer would get somewhat stronger” but “that is not the case,” Wentworth said.