Drug overdose deaths in the US have fallen for the first time since 1999, according to preliminary official data.
The Centers for Disease Control and Prevention (CDC) figures showed a drop of 5.1% in 2018 from the year before.
Health and Human Services Secretary Alex Azar said this was down to a decline in deaths linked to opioids.
US efforts "to curb opioid use disorder and addiction are working," he said in a statement, although he added the issue "will not be solved overnight".
The US is in the midst of an opioid crisis, with hundreds of thousands thought to have died over the last few decades.
Fatal drug overdose numbers rose every year from 1999 to 2017, including a sharp spike between 2014 and 2017.
Experts partially blame the overprescription of powerful and addictive painkillers for the epidemic.
The CDC research shows that an estimated 68,557 people died in 2018, down from 72,224 people in 2017.
Deaths from natural and semi-synthetic opioids - painkillers like morphine, codeine and oxycodone - fell by 14.5%, the sharpest drop for any drug category.
However, those linked to synthetic opioids like fentanyl still rose. Fentanyl is said to be up to 100 times stronger than morphine and has flooded the illegal US drugs market.
The numbers of deaths attributed to cocaine and methamphetamine also rose in 2018.
"Lives are being saved, and we're beginning to win the fight against this crisis," Mr Azar's statement said, praising efforts by the Trump administration and community efforts across the US for the shift.
But while he described the decline as "encouraging", Mr Azar said "by no means have we declared victory against the epidemic or addiction in general".
"This crisis developed over two decades and it will not be solved overnight."
The Washington Post reports that the biggest US drug companies gave out 76 billion oxycodone and hydrocodone pain pills between 2006 and 2012.