RNAi (RNA Interference) has been recently found as an innate cellular process activated when a double-strand RNA (dsRNA) molecule enters the cell causing the degradation of RNAs of identical or closely similar sequences, including mRNAs. It would suppress the expression of specific genes. It proves to be a more efficient tool than the antisence method with more specificity and now it is the focus of researchers allover the world. People are trying to find ways to make RNAi of an efficient clinical method but they also found that it is a long way to go before it becomes successful at last. To make an analysis of the problems and solutions during the process based on the fundamental knowledge that were already known are reviewed.