In this study, we aimed to investigate the genotoxicity (via analysis of micronuclei), serum levels of homocysteine, vitamin B12 and folic acid, and C677T (rs1801133) and A1298C (rs1801131) polymorphisms in the MTHFR gene in patients with exacerbated psoriasis vulgaris treated by Goeckerman therapy. This evidence concerns the gene MTHFR and psoriasis vulgaris.