Treatment of perianal fistulas in patients with Crohn’s disease with injections of cultured adipose-tissue-derived stem cells is effective but expensive and time-consuming. In a prospective trial in 21 patients with complex perianal fistulas, researchers injected freshly collected autologous adipose tissue instead of stem cells. Additional injections were offered in the absence of complete fistula healing at 6 weeks or at subsequent relapse. After a 6-month follow-up period, fistulas had healed completely in twelve patients (57%), with nine patients requiring one injection, two patients requiring two injections and one patient requiring three injections. Fistulas ceased secretion in three further patients and one patient reported reduced fistula secretion. Short-term proctalgia was the predominant adverse effect.