They said Gosnell, with the help of three co-defendants, distributed more than 500,000 pills containing oxycodone, 400,000 pills containing alprazolam and more than 19,000 ounces of a cough syrup containing codeine from June 2008 to February 2010 for no legitimate medical purpose.
The co-defendants aided Gosnell by taking customers' orders for prescription refills and selling the scripts, the indictment said.
After charging customers an initial fee of $115 for an office visit, which was later increased, Gosnell, beginning in July 2009, began charging customers for refill prescriptions at the time of pickup, typically $20 for those paying in cash and $10 for those with insurance, prosecutors said.
Gosnell faces a mandatory minimum 20 years in a federal lockup if convicted of all drug charges.
The indictment said Gosnell went from writing several hundred prescriptions a month for the drugs to more than 2,300 a month by January 2010.
Prosecutors said that customers had the prescriptions filled at pharmacies and that the drugs were later sold on the street for cash.
A Philadelphia grand jury indicted Gosnell last January on separate murder charges. He has pleaded not guilty in that case and is awaiting a March 2013 trial date in state court.
Gosnell has been charged with murder in the 2009 death of a Virginia woman undergoing an abortion and with killing seven newborns by severing their spinal cords with scissors.
