Purpose of reviewMessenger RNA, transfer RNA and ribosomal RNA were defined long ago as essential components for transmission of genetic code from DNA. However, there are many other, less commonly recognized RNAs, such as ribozymes and small interfering RNAs, which are distinguished by their ability to inhibit RNA function. This review describes the basic molecular concepts and potential therapeutic applications of RNA inhibition by a variety of molecules, including ribozymes, antisense oligonucleotides, aptamers and small interfering RNAs.Recent findingsA tremendous amount of data has recently emerged about double-stranded small interfering RNAs, which bind and degrade corresponding messenger RNAs by a process called RNA interference. Though native small interfering RNAs have been shown to be biologically relevant in animals and plants, synthetic types have rapidly become powerful tools for post-transcriptional inhibition of specific gene products to determine functional consequences in simple organisms and in-vitro model systems. More established means of RNA inhibition, such as with ribozyme and antisense strategies, continue to be viable options for in-vitro experiments, and form the basis for many ongoing clinical trials.SummaryRibozymes, antisense oligonucleotides, aptamers and small interfering RNAs are potentially useful reagents for in-vitro investigation and for treatment of kidney and hypertension diseases.