Para-chlorophenylalanine (PCPA), a tryptophan hydroxylase inhibitor consumes 5-hydroxytryptaminein the brain that leads to insomnia. In recent years, the establishment of an insomnia animal model using PCPA has beenrecognized and widely used for animal experiments because of its simplicity and practicality. However, the low solubility ofPCPA in water and the difficulty of its injection has hindered the progress of experiments. In this paper, we review literatureregarding the use of PCPA, summarize the method for using PCPA in experiments, and discuss the best way to use PCPA.