Walgreens expects to reach about half the country by the end of the year with a new service that lets people see doctors for minor ailments without leaving home, through smartphone, tablet or computer. The nation’s largest drugstore chain is expanding a smartphone application it started testing last December to tablets and personal computers and plans to make it available in 25 states.

The growth comes as major insurers UnitedHealth Group and Anthem prepare to expand their own non-emergency telemedicine services to about 40 million more people by next year.

Doctors have used video feeds and other technology for years to treat patients in remote locations, but experts say growing smartphone use and customer demand are fueling a rapid expansion into everyday care the family doctor used to handle.