冬蟲夏草是著名的強壯滋補中藥，主要作用為「保肺氣、實腠理」，「益腎，補精髓」，可補虛損，益精氣，止咳化痰，一般民眾常使用冬蟲夏草在慢性腎炎、慢性氣管炎等發炎反應性疾病。為瞭解人工培養之冬蟲夏草的抗發炎作用，本實驗針對人工培養之冬蟲夏草對於健康人體嗜中性白血球及淋巴球的影響進行研究。實驗徵求健康受試者以隨機雙盲方式分成實驗組及對照組，並給予人工培養之冬蟲夏草膠囊（實驗組）及安慰劑（對照組）。實驗組冬蟲夏草劑量為1.5 公克，一天兩次，一日服用總劑量為3 公克，服用三個月，於服用前、服用一個月、兩個月及三個月各抽血檢驗嗜中性白血球吞噬率、prostaglandin E2 （PGE2）、leukotriene C4 （LTC4） 以及CD4（+）與CD8（+）T淋巴球比例。結果顯示嗜中性白血球吞噬作用在實驗組有下降並有統計上差異（P<0.05）。嗜中性白血球經由100 μg/ml lipopolysaccharide 刺激後所產生prostaglandin E2數值在實驗組有下降並有統計上差異（P<0.05）。單核淋巴球實驗前及實驗後CD4（+）與CD8（+）T淋巴球的比值有偏向CD4（+）T淋巴球的趨勢並且有統計上的意義（P<0.05）。顯示人工培養之冬蟲夏草菌絲體可經由抑制嗜中性白血球吞噬作用及抑制cyclooxygenasepathway，並調控CD4（+）及CD8（+）淋巴球細胞數的比例，以達到抗發炎的作用。Cordyceps sinensis is known as a medicinal herb that can be used to enhance chi and kidney function in Traditional Chinese medicine that was commonly used by folks in treating inflammatory diseases such as chronic nephritis and brochitis. The purpose of this study was to investigate the anti-inflammatory effects of cultured Cordyceps sinensis on neutrophil- and T lymphocyte- mediated immune responses. In the present study, we recruited healthy volunteers to randomly take either 1.5 gm of mycelium of cultured Cordyceps sinensis or placebo twice daily for three months. Blood samples were collected from volunteers to define their phagocytotic function of neutrophils, PGE2 level and LTC4 level produced by neutrophils as well as CD4/CD8 ratio of T lymphocytes before the study, and monthly, until the third month when the study completed. In the experimental group treated with cultured Cordyceps sinensis, neutrophil phagocytosis decreased significantly (P<0.05). After 100 μg/ml lipopolysaccharide incubation, the amount of PGE2 produced by neutrophils also decreased significantly (P<0.05). Three months treatment with cultured Cordyceps sinensis significantly increased CD4/CD8 ratios. In summary, cultured Cordyceps sinensis significantly decreased the phagocytotic function of neutrophils, inhibited cyclooxygenase pathway and increased CD4/CD8 ratios. We concluded that the mycelium of cultured Cordyceps sinensis has a moderate anti-inflammatory effect.