AIM: To elucidate the influences of H pylori infection on oral iron treatment for iron deficiency anemia (IDA). METHODS: A total of 86 patients were divided into two groups: group A, receiving ferrous succinate combined with triple therapy for H pylorieradication, and group B (control), treated with ferrous succinate only. During treatment of IDA, dynamic changes in hemoglobin (Hb) level, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), serum iron (SI), and serum ferritin (SF) were compared between the groups. RESULTS: Hb was slightly higher in group A at d 14 after the start of triple therapy for H pylori eradication (P ＞ 0.05). After the therapy, the increase of Hb in group A became significantly faster than that in group B (P ＜ 0.05). At d 56, the mean Hb in group A reted to the normal level, however, in group B, it was lower than that in group A (P ＜ 0.05) although it had also increased compared with that before oral iron treatment. The MCV and MCH in group A recovered to the normal level, and were much higher than those in group B (P ＜ 0.05) at d 21. In Group B, the MCV and MCH remained at lower than normal levels until d 42 after the start of therapy. And then, they reached a plateau in both groups and the differences disappeared (P ＞ 0.05). The SF in group A was higher than that in group B (P ＜ 0.05) 28 d after the treatment and its improvement was quicker in group A (P ＜ 0.05), and the difference between the two groups was even more significant (P ＜ 0.01) at d 56. The SI in group A was higher than that in group B (P ＜ 0.05) at d 14 and this persisted until d 56 when the follow-up of this research was finished. CONCLUSION: Treatment of H pylori can enhance the efficacy of ferrous succinate therapy in IDA patients with H pylori-positive chronic gastritis.