O-1812 is an eicosanoid derivative related to anandamide that acts as a potent and highly selective agonist for the cannabinoid receptor CB<sub>1</sub>, with a K<sub>i</sub> of 3.4 nM at CB<sub>1</sub> and 3870 nM at CB<sub>2</sub>. Unlike most related compounds, O-1812 is metabolically stable against rapid breakdown by enzymes, and produces a cannabinoid-like discriminative effect in rats, which is similar but not identical to that produced by cannabinoid drugs of other chemical classes.