DOM is a psychdelic substituted amphetamine with effects similar to LSD. It has a slow come up, and an extremely long duration.
DOM first saw human use in 1967, when tablets sold under the street name 'STP' started to become popular in the Haight-Ashbury District of San Francisco. These tabs contained an excessively high dose in the range of 15 to 20mg. This, combined with the long onset of the drug, led to numerous non-fatal overdoses.