The fire broke out on Tuesday morning at about 4:00 in the store near 10th and Reed streets, in South Philadelphia.
Flames apparently spread from several storage containers in the rear of the store, into the body of the building and up through the roof.
Firefighters had to cut through the steel containers to get to the source of the flames.
It took almost an hour for crews to get the blaze under control.
The fire has gutted the pharmacy area of the store.
There are no reports of injuries, and no word yet on a cause.
