This study evaluated two oral sedative regimens for the conscious sedation of pediatric dental patients (mean age 37.0 months) unmanageable by traditional behavior management techniques. Regimen A included chloral hydrate (Noctec--E.R. Squibb and Sons, Princeton, NJ) at 50 mg/kg with 25 mg hydroxyzine pamoate (Vistaril--Pfizer Laboratories, New York, NY), plus meperidine (Demerol--Winthrop-Breon, New York, NY) at 1.5 mg/kg. Regimen B included chloral hydrate at 50 mg/kg with 25 mg hydroxyzine pamoate. In a crossover research design, 10 patients were assigned randomly to receive one regimen, to be followed by the alternative regimen during the second appointment. The primary purpose of this study was to determine if meperidine would improve patient behavior, and increase the prevalence of respiratory compromise. A secondary purpose of the study was to develop an objective method to assess behavior during the conscious sedation of pediatric dental patients. Results revealed that the addition of oral meperidine to chloral hydrate and hydroxyzine pamoate resulted in improved behavior (P less than 0.01) during local anesthetic injection, rubber dam delivery, and the operative dental procedure. There was no increase in the prevalence of respiratory compromise with the addition of meperidine.