In the case of the next combined polymorphism, i.e., c.-1849C > A – IDO1 (rs3824259) and c.803+221C>A – TPH1 (rs1800532), we confirmed that the C/C-C/A and A/A-C/A genotypes decreased the risk of stroke occurrence, while the C/A-C/C and A/A-A/A genotypes increased this risk in the studied population. The gene discussed is IDO1; the disease is Stroke.