In the case of illegal drugs, supply reduction efforts generally involves attempts to disrupt the manufacturing and distribution supply chains for these drugs, by both civilian law enforcement and sometimes military forces. This approach, sometimes characterized as the "War on Drugs", has been the dominant approach to drugs policy since the 1960s.
There is little or no evidence showing that supply reduction methods can be successful as a means to reduce the supply of illicit drugs. For example, the retail price of cocaine in the US in 2007 was less than half the price in 1984, despite massive investments by the US government in supply reduction strategies. Some analysts have argued that the abject failure of supply reduction in the US actually contributed to a significant and lasting reduction in crime and violence beginning in the 1990s, when cocaine prices hit record lows. 
- "Supply, demand and harm reduction". Burnet Institute, The Centre for Harm Reduction. 14 April 2004.
- Marcus Roberts, Mike Trace and Axel Klein (2004). "Report Three: Law Enforcement and Supply Reduction". Beckley Foundation Drug Policy Programme.
- Justin Rood (2009). "Cheap High: Cocaine Prices Still Falling". ABC News.
- Llewellyn Hinkes-Jones (2011). "How the Plummeting Price of Cocaine Fueled the Nationwide Drop in Violent Crime". The Atlantic Cities.