Objective : There are many reports that acupuncture has thermoregulatory effects on human and animals. To investigate the effect and mechanism of antipyretic action of acupuncture, we observed the body temperature and cytokine expressions in the hypothalamus of rats. Methods : Lipopolysaccharide (LPS, i.p., 2.5mg/kg) was injected to conscious rats (Sprague-Dawley, male, n=4l) to cause hyperthermia and simple needling (stainless steel, 0.25 mm o.d., 5 mm insertion for 10 sec with no manipulation) was performed bilaterally with the measurement of rectal temperature. Next, we sacrificed rats to remove brain and determined the level of mRNA for interleukin-6 (IL-6), $interleukin-1{eta}{;}(IL-1{eta})$, interleukin-2 (IL-2) and $interferon-{gamma}{;}(IFN-{gamma})$ in the hypothalamus by using reverse transcriptase-polymerase chain reaction (RT-PCR). Resul1s : Needling on forepaw (acupoint HT8) and needling on hindpaw (acupoint BL66 and acupoint LR2) significantly inhibited LPS-induced fever of rats (P<0.01, 10 min after treatment respectively), but same treatment on proximal tail (non-acupoint) did not cause any change on fever. The levels of IL-6 and $IL-1{eta}$ mRNA in the hypothalamus was significantly enhanced by LPS-injection, while the level of IL-6 and $IL-1{eta}$ mRNA was markedly reduced after treatment on BL66 (P<0.01). Treatment on forepaw reduced it slightly, but not significantly. Equivalent stimulation on proximal tail did not cause any changes. Conclusions : Our results indicate that acupuncture stimulation on various body parts has differential thermoregulatory effects on LPS-induced fever of rats with site-specificity. And, we suggest that its antipyretic action might be accompanied with the suppression of hypothalamic production of pro-inflammatory cytokine of immune system, IL-6 and $IL-1{eta}$.