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. Here, CYP3A4 is linked to fungal infectious disease.