The re-emergence of the monkeypox virus (MPXV) three years after the start of the SARS-CoV-2 epidemic further emphasizes the need to develop broad spectrum antivirals (BSAs) that might control the spread of poorly understood pathogens. The induction of innate immune responses to a viral infection triggers rapid expression of type-I-interferon (IFN-I), which subsequently results in the differential expression of more than 300 genes that foster an antiviral state. Whereas the expression of a majority of these “interferon-stimulated genes” (ISGs) are enhanced, , other ISGs’ expression are suppressed, including some involved in lipid metabolism which is hijacked to promote viral growth. Herein, we report that the expression of fatty acid synthase (FASN), an enzyme involved in de novo biosynthesis of fatty acids, was significantly reduced upon MPXV infection. Moreover, MPXV infection was impaired in FASN knockout cells, and biological inhibitors of FASN significantly inhibited MPXV. Interestingly, the ISG chosterol-25-hydroxylase was induced in MPXV-infected cells, and its enzymatic product, 25-hydroxychlosterol (25HC), blocked MPXV infection. Overall, this study indicates that 25HC and FASN inhibitors are highly potent BSAs and may have therapeutic applications in combating understudied infectious diseases in early outbreak settings when targeted therapies have not yet been developed.