In the low PLT (Q1) and normal MTHFR 677 genotype (CC/CT) subgroups, folic acid treatment decreased in a 59% (HR: 0.41; 95% CI: 0.23–0.72; p = 0.002) and 65% (HR: 0.35; 95% CI: 0.18–0.66; p = 0.001) risk of first stroke and ischemic stroke. This evidence concerns the gene MTHFR and ischemic stroke.