The convenient RNeasy Lipid Tissue protocol integrates QIAzol phenol/guanidine-based lysis with silica-membrane RNeasy RNA isolation for high yields of total RNA. The combination of organic extraction and chaotropic disruption contributes to the high lysis efficiency of QIAzol Lysis Reagent, enabling use of larger amounts of fatty tissues in the RNeasy procedure. RNA partitions to the upper, aqueous phase, while DNA partitions to the interphase and proteins to the lower, organic phase or the interphase. Ethanol is added to the aqueous phase and the sample is applied to the RNeasy spin column.