The distribution of MDR-1 genotypes were found to be 20.0% 9 for CC, 60.0% 27 for CT, and 20.0% 9 for TT in the asthma group and 44.4% 12 for CC, 51.9% 14 for CT, and 3.7% 1 for TT in the control group. This evidence concerns the gene ABCB1 and asthma.