Abstract: The present invention provides a method for inactivating RNase which generally presents in a sample such as biological sample (especially an excrement sample), or in a sample such as a living body-derived sample (especially an excrement-derived sample) obtained by separation of an RNA-including body therefrom or the like; a method for extracting and detecting RNA from the sample. An RNA extraction method, comprising the steps of: obtaining a mixture under a heating condition, said mixture comprising: a sample comprising an RNA-including body and RNase, and an alkaline treating reagent comprising at least a reducing agent, and having pH of 8.1 or higher, and conducting inactivation of the RNase and extraction of RNA from the RNA-including body by keeping the mixture under the heating condition. An RNA detection method, comprising conducting RNA amplification reaction by mixing a treated sample liquid comprising RNA extracted by the extraction method and an amplification reaction solution.