Poppers should not be included in a crackdown on so-called legal highs because they are not "psychoactive", Government advisers have said.
Selling the party drug has been earmarked for criminalisation under new laws which come into force next month.
The Psychoactive Substances Act will introduce a blanket ban on the production, distribution, sale and supply of new psychoactive substances (NPSs).
In a letter to the Home Office, the Advisory Council on the Misuse of Drugs (ACMD) said in its view poppers do not fall within the scope of the current definition of a psychoactive substance in the legislation.
Consequently, there is no need for the substance to be exempted, it added.
The Home Secretary has the power to make amendments to a list of exempted substances under the Act.
The ACMD said its "consensus view is that a psychoactive substance has a direct action on the brain and that substances having peripheral effects, such as those caused by alkyl nitrites, do not directly stimulate or depress the central nervous system."
Poppers, the name given to a group of chemicals called alkyl nitrites, are popular among gay men. They are normally sniffed from a bottle, producing a short head-rush.
In 2011, the ACMD concluded that misuse of the drug "is not seen to be capable of having 'harmful effects sufficient to constitute a social problem'".
Its letter, published on Wednesday, said the opinion "remains valid".
It added that reports of ocular damage, although rare, are "serious" and should be carefully monitored, while the use of poppers may be more risky for people with heart conditions or abnormal blood pressure.
Minister Karen Bradley said: "The landmark Psychoactive Substances Act will fundamentally change the way we tackle new psychoactive substances - and put an end to the game of cat and mouse in which new drugs appear on the market more quickly than Government can identify and ban them.
"We have noted the advice of the Advisory Council on the Misuse of Drugs and we intend to respond shortly."