N.H. Rev. Stat. Ann. § 644:5-a

A person is guilty of a violation if he or she purposely smells or inhales the fumes of any substance having the property of releasing toxic vapors, for the purpose of causing a condition of intoxication, euphoria, excitement, exhilaration, stupefaction, or dulled senses of the nervous system, or possesses, buys or sells any such substance for the purpose of violating or aiding another to violate this section. This section does not apply to the inhalation of anesthesia for medical or dental purposes.