In a study of 21 primates, treatment with oral ibuprofen significantly reduced the force required for tendon gliding following flexor tendon injury in zone II. Tendons that were partially lacerated but not repaired required less force for tendon motion than those repaired. Ibuprofen also reduced the breaking strength of completely divided and repaired extensor tendons. The addition of a piece of chromic suture buried across the extensor tenorrhaphy site significantly increased the breaking strength of the repair in control and treated animals alike. These findings were observed at 4 and 6 weeks after tendon injury and repair. No adverse reactions to the medication were observed.