Background: Fever in children is a common and usually benign symptom. It is known that antipyretic treatment is ineffective in the prevention of simple febrile seizures. Caregivers' administration of antipyretic medications to children has been reported, but data concerning the formulations used, actual doses administered, and effects of ethnicity and socioeconomic status on administration practices are incomplete. Objective: The aim of this study was to identify the factors affecting antipyretic administration (higher-than-recommended doses in particular) by caregivers to their febrile children in 2 differing cultural-ethnic backgrounds. Methods: This cross-sectional survey study, conducted from January to March 2002, was part of a larger, ongoing survey study of the differences in care givers' knowledge, beliefs, and attitudes concerning children's fever in the 2 major cultural-ethnic groups in the Negev District in Israel: Jews and Bedouin Moslems. It was conducted at the Pediatric Emergency Department (PED), Soroka Medical Center, Beer-Sheva, Israel. A structured questionnaire was administered to Jewish and Bedouin Moslem parents or usual caregivers of young (age, 0-60 months) children attending the PED due to fever. Each child's weight was obtained from the PED medical record. After completion of the interview, the reported antipyretic dose per kilogram of body weight was calculated. Less-than-recommended dose was defined as <9 mg/kg for acetaminophen and <4.5 mg/kg for ibuprofen. Higher-than-recommended dose was defined as >16.5 mg/kg for acetaminophen and >11 mg/kg for ibuprofen. Results: The caregivers of a total of 201 children (mean [SD] age, 20  months; mean [SD] weight, 10.4 [4.0] kg) were included in the study. The study included 101 Jewish and 100 Bedouin Moslem caregivers. The proportion of people surveyed who were parents was 98%; grandmothers, 2%. Differences existed between the 2 cultural-ethnic groups in the source of knowledge regarding antipyretic use in children (a significantly larger proportion of Jewish caregivers received their knowledge concerning antipyretic use from package inserts compared with Bedouin caregivers [25.7% vs 6.0%; P < 0.001], and a significantly lower proportion of Jewish caregivers used "other" sources [15.8% vs 39.0%; P < 0.001]). Most (65.2%) caregivers indicated that they administered antipyretics for no or minimal elevations in body temperature (<-38°C); 52.7% administered individual acetaminophen doses within 10% of the recommended dose, 34.8 % administered a higher-than-recommended dose, and 21.4% repeated the dose at intervals of ≤3 hours. More Bedouin than Jewish caregivers exposed their children to higher-than-recommended antipyretic doses (48.0% vs 21.8%; P < 0.001). After adjusting for maternal education and work-for-income status, child's age, child's order in the family, and number of children in the family, a significant and independent inverse relationship was found between child's weight and higher-than-recommended acetaminophen doses, in which for each additional kilogram of body weight, a 30% decrease in the proportion of children administered higher-than-recommended doses was found (odds ratio [OR], 0.7 for each additional kg; 95% CI, 0.59-0.89; P = 0.002). In addition, a significant and independent relationship was found between the formulation of acetaminophen and the administration of higher-than-recommended doses (OR, 4.9; 95% CI, 2.32-10.23; P < 0.001), with rectal suppositories related to the administration of higher-than-recommended dose by 4.9-fold. Conclusions: The results of this survey concerning antipyretic treatment of children by their Jewish and Bedouin Moslem caregivers suggest that lighter body weight and the use of acetaminophen rectal suppositories were associated with the administration of higher-than-recommended doses of acetaminophen. Recommended doses of acetaminophen must be based not on the age but on the weight of the child.