Enhancers are key cis-acting gene regulatory elements in eukaryotes, which can effectively promote the expression of target genes. Emerging evidence showed that enhancers in activation state could be transcribed to enhancer RNAs (eRNAs), the processes of which are regulated by various signaling systems and actions of signal-dependent transcription factors. Compared with the other transcripts (e.g. lncRNA, mRNA), eRNAs have shorter sequences, lower stability, and higher tissue specificity. eRNAs play roles in the initiation or stabilization of enhancer-promoter looping, and promote the expression of target genes. Recent studies have further showed that eRNAs have crucial roles in biological processes, such as development and disease initiation and progression. However, functional studies of eRNAs are currently lacking, and the regulatory mechanisms of eRNAs are still uncertain. Herein, we focus on the features, research methods and functional properties of eRNAs, and discusse the possibility of using eRNAs as therapeutic targets. We hope this discussion might provide some insights for further research on eRNAs.