The CRISPR/Cas9 system represents an adaptive immunological defense mechanism observed in bacteria and archaea, which has evolved to protect these organisms from persistent viral and plasmid assaults. This system is comprised of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) proteins. By modifying the simplest type II CRISPR system and introducing a special small guide RNA (sgRNA) and Cas9 endonuclease into the cell, it is possible to cut double-stranded DNA at a specific location and realize knockout or knock-in. CRISPR/Cas9 system has many applications in biological and scientific research fields due to its efficient gene editing function, which makes up for the shortcomings of traditional transgenic technology, such as random integration and genetic instability, and has a broad development prospect. This paper comprehensively discusses the CRISPR/Cas9 technology’s applications in drug discovery and the drug development, such as screening and targeted editing of functional genes, screening and validating drug targets, fabricating animal bioreactors, constructing animal models, and treating genetic diseases, etc. It also discusses the risks and prospects of CRISPR/Cas9 technology.
