The U.S. Justice Department is accusing Walgreens of filling millions of prescriptions in the last decade and more without a legitimate purpose, including for dangerous amounts of opioids, according to a lawsuit filed this week.

The U.S. Justice Department on Friday accused pharmacy chain operator Walgreens Boots Alliance of contributing to the U.S. opioid epidemic by filling millions of unlawful prescriptions for addictive painkillers and other drugs.

The Department of Justice sued pharmacy giant Walgreens for allegedly dispensing millions of unlawful prescriptions. Walgreens from August 2012 until the present "knowingly" filled those prescriptions, which "lacked a legitimate medical purpose, were not valid, and/or were not issued in the usual course of professional practice," the DOJ said.

The U.S. Justice Department said on Friday it has filed a lawsuit alleging that pharmacy chain operator Walgreens knowingly filled millions of prescriptions that lacked a legitimate medical purpose.

The Department of Justice sued Walgreens Boots Alliance Inc. for allegedly dispensing opioids and other controlled substances at pharmacies across the US while ignoring red flags that the prescriptions were likely illegal.

The pharmacy chain since August 2012 filled prescriptions that lacked a legitimate medical purpose, were invalid or weren’t issued in professional practice, the Justice Department said.