Based on these observations, we sought to determine the frequency of the CYP2C19 rs4244285, rs4986893, rs72552267, and rs12248560, CYP3A4 rs4646437, ABCB1 rs1045642, and FMO3 rs2266782 polymorphisms in a Thai population and to determine the association between voriconazole plasma concentrations and these genetic variants in Thai patients with invasive fungal infections. This evidence concerns the gene CYP2C19 and fungal infectious disease.