Opium has been grown in Turkey, Iran, Pakistan, Afghanistan, India, Nepal, Myanmar (formally Burma), Thailand, Laos, China, and Vietnam.
It is also believed to be grown in the central post-Soviet states, including Kazakhstan and Kyrgyzstan, Mexico (allegedly imported by immigrant Chinese opium users), and Colombia (reportedly as part of a collaboration between South-East Asian and Colombian drug traffickers).
According to a United Nations Office on Drugs and Crime report published in the mid-2000s, large amounts of opium are only cultivated in Myanmar, Afghanistan, and Colombia.
Of these countries, opium replacement has been implemented in Thailand, Laos, Myanmar, Vietnam, Pakistan, Mexico, and Afghanistan.
Laos has experienced steep declines in cultivation, but former opium farmers are often left destitute due to the scarcity of legal, alternative crops.
The opium replacement project in Afghanistan is slow, due to the large scale of cultivation, size of the country, poor security, destruction of infrastructure, and weakness of government institutions.
The crops include: cabbage, lettuce, kidney beans, tea, coffee, peaches, apples, herbs, and decorative flowers.
Despite the presence of opium replacement projects, the world's supply of illicit drugs is continually rising, while prices are falling.
Opium replacement projects are typically implemented by national government agencies with the support of an international donor.
In 1988 when the AD project started in Doi Tung the total area under illicit poppy cultivation in Thailand was only 2811 hectares (pg.