Walgreens is being sued by the DOJ for allegedly knowingly filling prescriptions without legitimate medical purposes.

• Walgreens was sued by the Department of Justice for allegedly distributing unlawful prescriptions in millions.
• Since August 2012, Walgreens has been filling prescriptions without a legitimate medical purpose, validity, or in the usual course of professional practice, according to the DOJ.

On Friday, the Department of Justice announced that it had filed a lawsuit against pharmacy giant for allegedly issuing millions of illegal prescriptions.

Walgreens, from August 2012 to the present, "knowingly" filled prescriptions that lacked a legitimate medical purpose, were not valid, and/or were not issued in the usual course of professional practice, according to the DOJ.

The DOJ's Civil Division, led by Principal Deputy Assistant Attorney General Brian Boynton, stated that this lawsuit aims to make Walgreens responsible for its failure to fulfill its duties for numerous years while dispensing hazardous opioids and other drugs.

Walgreens pharmacists filled millions of prescriptions with "clear red flags that indicated the prescriptions were highly likely to be unlawful," according to Boynton.

Walgreens pharmacists were pressured to fill prescriptions without verifying their validity, resulting in the illegal distribution of millions of opioid pills and other controlled substances, according to Boynton.

The DOJ alleges that some Walgreens patients died of overdose deaths shortly after receiving invalid prescriptions filled at Walgreens.

The 300-page lawsuit was filed Thursday in U.S. District Court in Chicago.

CNBC has requested comment from Walgreens.

Walgreens allegedly issued written policies that reflected its understanding of legal obligations, but took other actions that prevented its pharmacists from complying with them.

The suit claimed that Walgreens prioritized profits over safety and compliance by implementing policies and practices that required pharmacists to fill prescriptions quickly, leaving them without enough time or resources to exercise their corresponding responsibility.

The suit alleges that one metric used was 'Verify By Promise Time' (VBPT), which required a pharmacist to fill a prescription within 15 minutes for a 'waiter' (a customer waiting in the pharmacy store for the prescription).

The suit stated that Walgreens tracked pharmacists who dispensed a low rate of controlled substances through its 'Non-dispensing Pharmacist Report.'

"Walgreens developed this metric due to the belief that pharmacists who declined to fill controlled-substance prescriptions undermined their customer service."