After cessation of kaolinite ingestion, we administered intravenous iron replacement therapy (total of 1000 mg) and the anaemia was corrected within 1 month (Hb 125 g/litre, MCV 79.4 fl, MCHC 333 g/litre, ferritin 13 ng/ml, soluble transferrin receptor 6.6 mg/ml). The gene discussed is GSTM1; the disease is anemia.