One native plant Indonesia are scattered in several regions, especially in the island of Timor NTT Province and has the potential to be developed into a medicinal plant that is Faloak (Sterculia sp.) Research on the Test of Effect Antipyretic Ethanol Extract Skin Stem Faloak (Sterculia sp.) In Mice White Males ( Mus musculus) strain Swiss Webster aims to determine the antipyretic effect of the ethanol extract of the stem bark faloak and effective as an antipyretic dose in mice induced DPT-HB vaccine. Extracts prepared by maceration method using ethanol 96%. White male mice used were 20 birds and were divided into 5 groups. Each mouse induced HB DPT vaccine at a dose of 0.0013 mL / 20 g BB. The first group was given paracetamol as a positive control at a dose of 1.3 mg / 20 g BB, the second group was given Na CMC as a negative control, and the three other groups faloak stem bark ethanol extract at a dose of 150 mg/kg, 300 mg/kg BW, and 600 mg/kg. Temperature measurement is carried out for 3 hours with a 30-minute interval. Measurement data were statistically analyzed using One Way ANOVA and advanced test Post Hoc LSD showed that the ethanol extract of bark faloak with a dose of 150 mg/kg and 300 mg/kg have an activity comparable with paracetamol, while extracts of 600 mg/kg has a more optimal antipyretic activity of paracetamol at a dose of 1.3 mg / 20 g BB.