Aim: This prospective randomized case control study aimed to investigate effect of oral agar administration in reducing total serum bilirubin (TSB) levels in full-term neonates with jaundice in comparison with control. Materials and methods: One hundred sixty full-term neonates were enrolled with TSB 10–19 mg/dl at first week of age from Assiut University Children’s Hospital. Neonates were divided according to TSB into outpatient group (n¼100) (TSB 10–15mg/dl) and admitted group (n¼60) (TSB > 15–19mg/dl). Outpatients group were subdivided into agar group received oral agar and control group received placebo. Admitted group were subdivided into agar group received oral agar plus phototherapy combination and control group received phototherapy alone. Neonates in the agar supplementation received oral agar 600 mg/kg/day dissolved in 10 ml distilled water twice daily till TSB decreased to 7mg/dl. Daily weight, stool frequency and side effects of treatment were observed for each group. TSB was determined pretreatment then serially every 48 h until TSB level reaching 7mg/dl. Results: Agar fed was effective in lowering TSB in neonates with TSB 10–15 mg/dl. TSB percentage changes were not significantly lower in agar-fed newborn with TSB >15–19mg/dl compared with control groups after 24 h and 7 days. Age fed shortened the time required to decrease TSB and increased stooling frequency. Conclusions: Oral agar supplemented feeding at 600mg/kg/day is safe for full-term neonates and useful in decreasing TSB and phototherapy duration. The efficacy of phototherapy in decreasing TSB level in neonatal hyperbilirubinemia can be augmented with oral agar usage.