Wikipedia.org:
Cheese is a
heroin-based
recreational drug that surfaced in the
United States in 2005 and came to the attention of the media inside and outside
[1] the United States after a string of deaths among
adolescents in the
Dallas/Fort Worth Metroplex, in 2006 and 2007.
Cheese is formed by combining heroin with crushed tablets of certain
over-the-counter cold medication, such as
Tylenol PM. Such cold medications contain
acetaminophen, the
active ingredient in
Tylenol, and the
antihistamine diphenhydramine, the active ingredient in
Benadryl[2] and a common opiate potentiator.[
citation needed] Cheese samples obtained in
north Dallas contained between 2% and 8% heroin, in contrast to the 30% commonly found in black tar heroin.
[3][4] Users commonly take the powder by
insufflation rather than by
intravenous injection. Another less common term for this mixture is "Tylenol With Smack" by analogy to the Tylenol With Codeine series.