Brown-brown is a purported form of cocaine mixed with smokeless gunpowder (not "black powder"). Smokeless powder often contains nitroglycerin, a drug prescribed for heart conditions, which might cause vasodilation, permitting the cocaine to move more freely through the body. This, in turn, is believed to allow for a more intense high. The term may also refer to heroin.
Brown-brown is reportedly given to child soldiers in West African armed conflicts. One former child soldier, Michel Chikwanine, has written a graphic novel with Jessica Dee Humphreys called Child Soldier, about the experience of being captured at the age of 5 by rebel fighters in the Democratic Republic of Congo, including being given brown-brown. "The rebel soldier who had hit me used a long, jagged knife to cut my wrist and rubbed powder into the wound. They called it Brown Brown – a mixture of gunpowder and a drug called cocaine. Right away, I began to feel like my brain was trying to jump out of my head."
According to Brendan I. Koerner, the use of cocaine mixed with gunpowder may be less prevalent than reports indicate, as cocaine would be difficult to source during armed conflicts, especially in the African continent. Brown pills that were referred to as cocaine were most likely amphetamine. The first actual documentation of the term "brown-brown" was a 2005 Norwegian NGO report that stated the term refers to heroin.