Refractory coeliac disease (RCD) is a rare diagnosis made after the exclusion of any disorder mimicking CD and after initial or subsequent failure of a strict gluten-free diet (GFD) to restore normal intestinal architecture. In the past, treatments such as steroids, cyclosporin and azathioprine have been tried, but literature on this subject consists mainly of case reports. Interleukin-10 (IL-10) may be beneficial in RCD because of its inhibitory effect on T-lymphocyte- and monocyte-driven immune responses. We performed a pilot, non-randomized, open label study to evaluate recombinant human IL-10 in RCD. IL-10 (8 mcg/kg) was administered subcutaneously, three times a week for 3 months in 10 RCD patients. Small bowel biopsies were taken at T = 0, T = 3 months and T = 9 months. The mucosal histopathology at 3 months was the primary end point for evaluation of efficacy. Evaluations of clinical features, malabsorption parameters and safety were made prior to, during and after treatment. Before treatment, all RCD patients had partial to total villous atrophy (Marsh III ABC). Two patients dropped out of the study: one because of headaches, the other because of thrombocytopenia. In the remaining eight patients, after 3 months of IL-10 treatment histology was unchanged in five patients, improved in two patients and deteriorated in one patient. Disappearance of villous atrophy was seen in only one patient. Three patients reported a clinical response, i.e. relief of fatigue, abdominal complaints and diarrhoea. After stopping IL-10 treatment the symptoms recurred. The laboratory parameters remained the same during treatment and in follow-up. In conclusion, in our study group of 10 RCD patients, IL-10 in the given dosage was not overall effective in our study group of RCD patients. Two dropped out because of side effects and in only one patient did we see a normalization of villous architecture.