en Pediatrics Pediatrics Original Article Original Article <span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="color:#0033ff;"><strong><em>Background</em></strong><em>:</em> </span>Fever is the most common complaint among the children admitted to health care centers. The aim of this study was to compare the anti-pyretic effect of diclofenac and high dose acetaminophen suppository in 1 to 6 years old children.<br> <span style="color:#0033ff;"><strong><em>Methods</em></strong><em>:</em></span> This double-blind clinical trial study was performed on 1-6-year-old children hospitalized in 17th Shahrivar Teaching Hospital, Rasht, Iran. Children were divided into two groups of 45 using a block randomization design. The first group received a high dose of acetaminophen suppository at a dose of 30 mg/kg and the second group received a diclofenac suppository at a dose of 1 mg/kg. The rectal temperature of the patients was measured using a digital thermometer at the time of drug administration, and one and three hours after that.<br> <span style="color:#0033ff;"><strong><em>Results</em></strong><em>:</em></span> 90 children were studied in two groups of 45 each. Temperature changes in the diclofenac group were significantly greater than the acetaminophen group, so from zero to 3 hours after administering diclofenac, the temperature decreased to 1.76&plusmn;0.95&deg;C. This reduction was lower in acetaminophen group (1.26&plusmn;0.49&deg;C, P=0.019).<br> <span style="color:#0033ff;"><strong><em>Conclusion</em></strong><em>:</em></span> Both acetaminophen and diclofenac suppositories significantly reduced the rectal temperature. However, the effect of rectal diclofenac on reducing temperature is more than rectal acetaminophen.</span></span> acetaminophen, diclofenac, fever, rectal, suppository 207 215 http://caspjim.com/browse.php?a_code=A-10-1805-1&slc_lang=en&sid=1 Houman Hashemian hashemian@gums.ac.ir 100319475328460028189 100319475328460028189 Yes Pediatric Diseases Research Center (PDRC), Guilan University of Medical Sciences, Rasht, Iran Marzie Fallah Khodadoost marzie.khodadoost@yahoo.com 100319475328460028190 100319475328460028190 No Pediatric Diseases Research Center (PDRC), Guilan University of Medical Sciences, Rasht, Iran.