This case report relates to the first-in-man use of a vessel occluder gel medical device as a fistula occluder in a repurposing strategy. A patient with chronic colocutaneous fistula received an off-label treatment with a thermoresponsive Poloxamer 407 gel (20%) via percutaneous administration and injected under endoscopic control. Treatment consisted in the association of esophageal stent placement and gel injection. The product was administered just after the stent placement at<20°C in its liquid form, gelling at body temperature to form a fistula plug. However, the stent was removed at day 26 because of major pain and the fistula was still present. Treatment was continued a total of 14 administrations of thermoresponsive Poloxamer 407 gel during 7 weeks via the external fistula orifice. The treatment reduced fistula orifice diameter from 4.0±0.5 to 1mm and fistula daily output decreased from 425±65 to 23±4mL, when comparing the months before and after treatment. Gel administration was not associated with any toxic effects. The therapeutic outcome remained stable 1 year after treatment. The external fistula diameter and the fistula output were similar to what was observed after the last Poloxamer 407 gel administration.