The colon can absorb iron.We propose an integrated approach utilizing colonic transendoscopic enteral tubing to deliver iron in different valence states, coupled with washed microbiota transplantation . This clinical trial aims to assess the feasibility, safety, and efficacy of this approach for the treatment of iron deficiency.

At least 60 subjects who meet all the inclusion criteria but do not meet any exclusion criteria will be enrolled in this study. Data of demographic characteristics, reticulocyte hemoglobin, ferritin and clinical outcomes will be collected. After treatment, they will enter the follow-up period for safety and efficacy evaluation.

Inclusion Criteria:

1. ferritin ≤30 μg/L;
2. feasible colonic TET placement (cephalic end in the ileocecal region);
3. completion of 3 WMT sessions.

Exclusion Criteria:

1. The patient has other co-morbidities that can lead to iron deficiency, such as acute gastrointestinal haemorrhage and menorrhagia.etc.
2. People who are allergic to iron or taking oral medications that interfere with iron absorption.
3. Patients with heart, brain, lung, liver, kidney and other serious diseases;
4. Patients do not cooperate to complete the clinical trial process;