A new article published in Expert Opinion on Drug Safety reported that guselkumab is a human monoclonal IgG1λ antibody which is used in the treatment of plaque psoriasis. Plaque psoriasis inhibits interleukin (IL)-23p19 subunit, reduces the proliferation of type 17 helper T (Th-17) cells, and thus, the production of Th-17-derived pro-inflammatory cytokines, specifically, IL-17 and IL-22. This article was based on a literature review which summarized data from PubMed search, relating proceedings and abstracts from relevant international conferences, assessment reports from European and United States regulatory agencies and treatment guidelines up to April 2018. In inference, it was stated that the central role of IL-23 in psoriasis pathogenesis is supported by genetic links of IL-23 and IL-23R alleles to psoriasis susceptibility. It was stated that previous clinical trials have demonstrated that sufficient inhibition of IL-23p19 results in rapid resolution of the disease. Hence, targeting IL-23, may be responsible for the high efficacy and durable responses of guselkumab, and can avoid adverse effects of IL-17A blockade, like mucocutaneous Candida infections or triggering/worsening of inflammatory bowel disease.