Walgreens is testing a new telemedicine service that lets patients see a doctor without leaving home or even visiting any of the drugstore chain’s clinics.

The Deerfield, Illinois, company says patients in California or Michigan can contact a physician around the clock through Walgreen’s mobile application for smartphones or tablet computers.

The visits cost $49, and doctors can diagnose and treat conditions like pink eye that don’t require a physical exam. They also can write prescriptions.

Walgreens is the nation’s biggest drugstore chain, with more than 8,200 locations.

Walgreens and other drugstore chains have been increasing their health care offerings. Walgreens runs 420 in-store clinics, and company officials say they believe the app will help build brand loyalty.

Health insurers like Anthem and hospital groups also offer virtual doctor visits.