The effects of Tarantula cubensis extract (TC; Theranekron®) on the experimentally induced rupture of the superficial digital flexor tendon (SDFT) 28 days post-injury (DPI) was studied in rabbits. Forty mature White New Zealand male rabbits were randomly divided into two groups. TC was repeatedly injected subcutaneously over the lesion 3, 7 and 10 days after tenotomy and surgical anastomosis. Clinical and ultrasonographic evaluations were conducted at weekly intervals. The animals were euthanized 28 DPI and the tendons were investigated for macroscopic, histopathologic, ultrastructural, biomechanical and percent dry weight parameters. Treatment reduced signs of acute inflammation and strongly ameliorated clinical symptoms, structural organization and biomechanical properties (p < 0.05). Apparently, TC is effective in restoring the clinical, morphological and biomechanical properties of the injured SDFT in rabbits and may be valuable in human and veterinary medicine.