At least a dozen members of Congress wore purple ribbons at President Trump’s State of the Union address on Tuesday night to help raise awareness about the country’s opioid epidemic.

In October, Mr. Trump declared that the crisis had become a “public health emergency.” Overdoses killed about 64,000 Americans in 2016, making it the leading cause of death for people under 50.

Mr. Trump mentioned the opioid crises again in his speech on Tuesday.

“We must get much tougher on drug dealers and pushers if we are going to succeed in stopping this scourge,” Mr. Trump said, noting the number of overdose deaths in 2016. “My administration is committed to fighting the drug epidemic and helping get treatment for those in need. The struggle will be long and difficult — but, as Americans always do, we will prevail.”

Lawmakers who donned the purple ribbons included Senator Chuck Schumer of New York, the Democratic leader, as well as Senators Maggie Hassan and Jeanne Shaheen, both Democrats of New Hampshire. Before the speech, Ms. Shaheen personally encouraged her colleagues in Congress to wear the ribbons, which her office distributed to lawmakers.