Party drug “hippie crack” caused a record number of deaths last year, according to official figures.
Fatalities doubled in 12 months among users of nitrous oxide, also known as laughing gas.
The drug, typically inhaled from a balloon, was linked to eight deaths in England and Wales in 2016 — up from four in 2015 and three each in 2014 and 2013.
It has led to more fatalities in the past four years than in the previous 20 combined, according to the Office for National Statistics.
The British government has made it illegal to supply, but it is readily available due to its medicinal and cookery uses.
Chronic users have died of suffocation or oxygen deprivation to the brain.
Public Health England warned: “It can be especially dangerous when mixed with alcohol.”
The Home Office added: “Drugs like nitrous oxide have already cost far too many lives, which is why this Government changed the law last year to make it illegal to supply.”
Separate Home Office stats show the amount of cocaine seized has surged by nearly a third in a year.
Authorities confiscated 5,516 kilograms (12,160 pounds) in England and Wales in 2016/17 — the most since at least 2003.