The anesthetic effects of clove-oil-derived eugenol were studied in the zebrafish, Danio rerio (Hamilton). Acute lethality and the effects of exposures to various dosages of eugenol were measured. The estimated 96-h LC50 for eugenol was 21 ppm. Times to induction and recovery from anesthesia were measured and compared with MS-222 under similar conditions. Eugenol induced anesthesia faster and at lower concentrations when compared to MS-222. The recovery times for fish exposed to eugenol were generally longer compared to similar concentrations of MS-222. Doses of 60-100 ppm eugenol produced rapid anesthesia with an acceptably short time for recovery. These findings suggest that eugenol could be an effective anesthetic for use with this species, and when compared to MS-222, its benefits include a lower cost, lower required dosage, improved safety, and potentially lower mortality rates.