近年來中醫保健越來越重視，使用溫和中草藥治療疾病，比起西醫較無副作用。目前中草藥對於人體有抗氧化、對干擾素有誘導作用、促進免疫系統增強以及調節體質等功能。能促進免疫系統
功能的草藥有人參、靈芝、香菇、當歸等；抗氧化的有三七、當歸精油、薑黃精油、人參和枸杞等。免疫，即是人體對疾病的抵抗力，亦是機體的一種保護性功能。人體主要借重免疫系統來對抗疾病，並且防癌、抗癌。免疫系統三大功能：（1）區別正常細胞和外來入侵物；（2）有免疫監視能力，防止細胞變異；（3）系統化排除入侵的病原、抗原。
根據最近食品工業發展研究所文獻記載，中草藥萃取物對細菌內毒素脂多醣ipopolysaccharide
（LPS）所誘發之促發炎細胞激素TNF-α、IL-6及IL-1β生成的抑制效果，證明中草藥的抗發炎效果。而芹菜素促進鼠類巨噬細胞RAW 264.7细胞增殖的功能，也說明其有增強免疫的功能。本研究是取用於中草藥中的白茅根作為研究，以人類單核球細胞THP-1作為實驗模式，探討白茅根對於免疫細胞的生物效應，希望藉由此次的實驗資料可提供更多的中草藥在免疫方面的生物功能。

Recently, people have paid more attention on Chinese herbal medicine in in disease treatment; because it low side effects than Western medicine. Chinese herbal medicine, which have many biological functions involving anti-oxidant activity, induction of interferon, promoting the immune system, and regulating the physique etc.. The panax ginseng, ganoderma lucidum, lentinula edodes and angelica sinensis can promote the function of the immune system; however, the pseudoginseng radix, angelica essential oil, turmeric essential oil and lycium chinese mill have anti-oxidant activities. Immunity is the body's capability to repel foreign substances and to defense diseases, is also a kind of protective function of an organism. The human body relies on the immune system to oppose the disease, give protection against cancer, and resist the cancer. Three major functions of immune system: (1) Recognition of the normal cells and exotic things; (2) There is immune surveillance to prevent the cell mutation; (3) Destruction of the pathogens and foreign antigens.
Recent literatures had demonstrated that some Chinese herbal medicines could inhibit the endotoxin LPS-induced inflammation, and apigenin had the ability to promote RAW 264.7 cell, a mouse macrophage cell line, proliferation. This research used lmperata cylindrical, one kind of Chinese herbal medicines, to treat the THP-1 cells, a human monocyte cell line, and analyzed cell viability with MTT assay. We hope the experimental results can give us more information about the biological functions of lmperata cylindrical in immune system.