Home Secretary Priti Patel has said she wants to "explicitly" remove any legal ban on supplying "poppers", a muscle-relaxing drug used by many gay men during sex.
In a letter to the Advisory Council on the Misuse of Drugs, she acknowledges the law on the liquid, whose scientific name is alkyl nitrites, is "uncertain".
Possession is not illegal but supply can sometimes be an offence.
Ms Patel has also ordered research into a rise in cocaine use among young men.
Poppers, used recreationally since the 1970s, give an instant "high" when inhaled, usually from a bottle, and work as a muscle relaxant.
The legal status of the drug is confused.
During a Commons debate in 2016, Conservative MP Crispin Blunt declared himself a user and asked for poppers to be specifically excluded from the Psychoactive Substances Bill - aimed at stopping the use of "legal highs" - arguing that banning supply would be "fantastically stupid".
MPs rejected his call and the bill passed into law without this exemption.
But the Advisory Council on the Misuse of Drugs (ACMD) advised ministers that poppers would not fall into the scope of the Psychoactive Substances Act because, unlike legal highs, they did not have a direct effect on the central nervous system.
However, this view was thrown into doubt in 2018 when a Court of Appeal judgement confirmed that substances which have only an "indirect" psychoactive effect, such as poppers, could still be covered by the legislation.
In her letter, Ms Patel tells Professor Owen Bowden-Jones, chairman of the ACMD, that "the lawfulness of the supply of poppers is uncertain".
She adds: "I am minded to remove this uncertainty by explicitly exempting poppers from the 2016 Act. I would seek the ACMD's advice on an exemption."
The government's Frank drugs information website says poppers have a "strong solvent smell" and "are often sold as 'room aromas', 'deodorisers' and 'leather cleaners', but they're not actually used in this way. They can be found in sex shops, clubs, market stalls and online."
It adds: "Because poppers increases blood flow and can relax the walls of the anus and vagina, some people take it while they're having sex."
It can be deadly to drink poppers and sniffing them can be dangerous, especially for people with heart problems, anaemia or glaucoma.
In her letter to Prof Bowden-Jones, the home secretary also asks experts to look at the impact of the coronavirus pandemic and lockdown on wider drugs use, particularly given the shrinking of the "night-time economy".
Ms Patel says her first "priority" is to find out why "the number of powder cocaine users has increased sharply over the past five years".
Much of this, she adds, has been driven by more white men under the age of 30 taking it, most notably in the East Midlands and south-west England.
The charity DrugWise suggests that, in 2018/19, 8.7% of people aged 16 to 24 reported taking a Class A drug, such as cocaine, ecstasy and heroin, in the previous year.
This proportion was the highest since 2002/3, it adds, with the increase being "mainly driven" by a rise in cocaine and ecstasy use.