EasyPrep miRNA Extraction Kit is designed for purification of total RNA, including miRNA and other small RNA molecules (from 20 nt ~200 nt), from cultured cells, and various animal and human tissues. EasyPrep miRNA Extraction Kit combines phenol/guanidine-based lysis of samples and silica membrane-based purification of total RNA. Buffer TRO, included in the kit, is a monophasic solution of phenol and guanidine thiocyanate, designed to facilitate lysis of tissues, inhibit RNases, and also to remove most of the cellular DNA and proteins from the lysate by organic extraction. The Kit utilizes a silica-based two-column system to enrich small RNA from various sample sources. From sample lysate, RNAs greater than ~ 200 nt are bound to the first column. The flow-through, enriched with small RNA molecules, is mixed with a higher concentration of ethanol to increase the binding affinity of small RNA to the membranes of the second column. Bound small RNA molecules are then eluted, ready-to-use, and free of large RNA molecules that can inhibit expression analysis of small RNA molecules, Purified RNA is suitable for different downstream applications.