Renal interstitial fibrosis is a common outcome of chronic renal diseases. Amygdalin is one of a number of nitrilosides, the natural cyanide‑containing substances abundant in the seeds of plants of the prunasin family that are used to treat cancer and relieve pain. However, whether amygdalin inhibits the progression of renal fibrosis or not remains unknown. The present study aimed to assess the therapeutic potential of amygdalin by investigating its effect and potential mechanism on the activation of renal interstitial fibroblast cells and renal fibrosis in rat unilateral ureteral obstruction (UUO). Treatment of the cultured renal interstitial fibroblasts with amygdalin inhibited their proliferation and the production of transforming growth factor (TGF)‑β1. In the rat model of obstructive nephropathy, following ureteral obstruction, the administration of amygdalin immediately eliminated the extracellular matrix accumulation and alleviated the renal injury on the 21st day. Collectively, amygdalin attenuated kidney fibroblast (KFB) activation and rat renal interstitial fibrosis. These results indicate that amygdalin is a potent antifibrotic agent that may have therapeutic potential for patients with fibrotic kidney diseases.