Along with the application of genetic polymorphism techniques to individualized treatment of clinical disorders, the screening of polymorphisms markers of serotonin (5-HT) transporter (SERT) is a hot-spot of researches on irritable bowel syndrome (IBS). In the present paper, the authors introduce 1) optimized schemes of diagnosis and treatment of IBS on the basis of syndrome-differentiation for acupuncture in combination with Chinese herbal medicines, and application of 5-HT transporter polymorphism, 2) application of genetic polymorphism to researches on IBS, and 3) feasibility of genetic polymorphism techniques for guiding individualized treatment of IBS. Up to now, serotonin transporter length polymorphic region (5-HTTLPR), serotonin transporter intron 2 variable number of tandem repeat (Stin 2 VNTR) and single nucleotide polymorphism rs 25531 in the long allele of the 5-HTTLPR have been identified. On the basis of the treatment of IBS, we need establishing a set of guide lines for the individualized acupuncture treatment. The genotyping methods for genetic polymorphism should be widely used in this research field. 5-HT TLPR/ Stin 2 VNTR/rs 25531 polymorphisms would have a bright future in the field of IBS research and treatment.