Mescaline of the genus "Echinopsis" are technically controlled substances under the Controlled Substances Act, they are commonly sold publicly as ornamental plants. In the United Kingdom, mescaline in purified powder form is a Class A drug. However, dried cactus can be bought and sold legally. Mescaline is considered a schedule 9 substance in Australia under the Poisons Standard (October 2015). A schedule 9 substance is classified as "Substances with a high potential for causing harm at low exposure and which require special precautions during manufacture, handling or use. These poisons should be available only to specialised or authorised users who have
Mescaline and activates the serotonin 5-HT receptor with a high affinity. How activating the 5-HT receptor leads to psychedelia is still unknown, but it is likely that somehow it involves excitation of neurons in the prefrontal cortex. Mescaline is also known to bind to and activate the serotonin 5-HT receptor. Difluoromescaline and trifluoromescaline are more potent than mescaline, as is its amphetamine homologue trimethoxyamphetamine. In the United States, mescaline was made illegal in 1970 by the Comprehensive Drug Abuse Prevention and Control Act, categorized as a Schedule I hallucinogen. The drug was prohibited internationally by the 1971 Convention on Psychotropic Substances.