Objective To explore the short and long-term therapeutic effect of helicobacter pylori (Hp) eradication and patho-genic role of Hp infection in the irritable bowel syndrome(IBS) and slow transit constipation(STC) .Methods 98 patients with pos-itive Hp infection which determined by 13C or 14C breath test ,suffered with either the IBS or STC and with concomitant dyspep-sia ,were treated with 7 days regimen of Hp eradication .All cases were re-examined with the 13C or 14C breath test one month after treatment and then divided into Hp positive group and Hp negative group according to the positive or negative Hp infection .And both groups were scored on the change of the habitual defecation and the stool consistency before one day and one month after Hp eradication .Results Hp infection in 87 cases was successfully eradicated ,11 cases failed .Among the Hp positive group ,the total effective rate decreased in comparison with before ,one day ,one month after Hp treatment (P<0 .05) .And among the Hp negative group ,the highest therapeutic effect was found in the diarrhea-IBS and lowest in the STC was found in the first day after treatment (P<0 .05) .Compared with the first day after treatment ,both IBS and STC showed significantly decreased therapeutic effect one month after Hp treatment(P<0 .05) .Conclusion Hp eradication couldn′t induce long term therapeutic effect in IBS and STC , which indicate Hp infection plays a minor role in the pathogenesis of both IBS and STC .The short term improvement of the defeca-tion and the stool consistence in some patients may relate to the change of the gut microbiota .