The Department of Justice and the Department of Health and Human Services announced charges against 601 defendants on Thursday, in a massive action taken against health care fraud.

The DOJ alleges that there was more than $2 billion in fraud perpetrated by health care professionals (including doctors and nurses), pharmacies and others. And while the focus was on billing scams to defraud Medicaid, Medicare, Tricare and private insurance companies — by submitting claims for things like medically unnecessary treatment, or treatments that were never provided to the patient — opioid schemes were also targeted.

Of the 601 defendants charged, 162 of them — including 76 doctors — were levied charges related to prescribing or distributing opioids or other narcotics.

In 2016, opioids contributed to 42,249 U.S. deaths and made up 66% of all overdose deaths.

Among the long list of charges on the DOJ’s website are two medical professionals in the Northern District of Iowa charged with opioid-related schemes, a Delaware physician who owned a pain management clinic charged with “unlawfully prescribing more than two million dosage units of oxycodone products,” and a pharmacy chain owner along with two others in Texas who were charged with using “fraudulent prescriptions to fill bulk orders for over one million pills of hydrocodone and oxycodone, which the pharmacy, in turn, sold to drug couriers for millions of dollars.”

Not included in this particular action by the DOJ and HHS are any major pharmaceutical companies, which have been blamed for contributing to the opioid crisis. The DOJ has not responded to Fortune’s request for comment on this.

In May, attorneys general from six states filed lawsuits against Purdue Pharma, the maker of opioid painkiller OxyContin, alleging among other charges that the company misrepresented or failed “to adequately disclose the risk of addiction of opioids.”

Purdue Pharma has been blamed for planting “the seeds of the opioid epidemic,” as one writer for the New York Times put it in a May piece about a confidential DOJ report that alleges Purdue knew about abuse of OxyContin.

“Suggesting that activities that last occurred more than 16 years ago are responsible for today’s complex and multifaceted opioid crisis is deeply flawed,” Purdue spokesman Robert Josephson said in a statement to the Times.

Purdue was the first company to make slow-release pain killers, which it aggressively marketed to physicians based on a phrase on the label not backed up by clinical trials, according to Marketplace’s The Uncertain Hour.

“We share public officials’ concerns about the opioid crisis, and while our opioid medicines account for less than two-percent of total prescriptions, we are committed to working collaboratively toward meaningful solutions to address this public health challenge,” Josephson said in a statement to Fortune, which continued:

We vigorously deny these allegations and look forward to the opportunity to present our substantial defenses. The majority of the states claim that Purdue acted improperly by communicating with prescribers about scientific and medical information that FDA has expressly considered and continues to approve. We believe it is inappropriate for these states to substitute their judgment for the judgment of the regulatory, scientific and medical experts at FDA.

Purdue ended its sales representative promotion of opioids in February.

In the past, at least 16 states have filed lawsuits against pharmaceutical companies for their alleged role in the opioid epidemic.