美國西格瑪Sigma-Aldrich是全球最大的化學試劑供應商，旗下包括Sigma、Aldrich 、Fluka、Rdh 等數個品牌，并且各個品牌涉及的領域都不相同，可以說Sigma-Aldrich公司的產品基本覆蓋了化學試劑的各個領域。
Sigma-Aldrich in United States is the world's largest supplier of chemical reagents, including Sigma, Aldrich, Fluka, Rdh and other brands, and each brand involves different fields, it can be said that Sigma-Aldrich's products basically cover all fields of chemical reagents.