Soluble epoxide hydrolase (sEH) catalyzes the conversion of epoxyeicosatrienoic acids (EpETrEs) to the corresponding DiHETrEs thereby diminishing their vasodilator activity. Inhibitors of sEH may therefore have clinical utility for treating hypertension and systemic inflammation. Epoxy fluor 7 is a sensitive fluorescent substrate for soluble epoxide hydrolase (sEH) that can be used to monitor the activity of both human and mouse enzymes. Hydrolysis of the substrate epoxide yields a highly fluorescent product that can be monitored at excitation and emission wavelengths of 330 and 465 nm, respectively. Epoxy fluor 7 is more stable in aqueous solution and offers about 2-fold better sensitivity than previously used colorimetric substrates such as NEPC.