ABSTRACT Background: Thiophenicol (TAP) is a broad-spectrum synthetic antibacterial drug structurally similar to chloramphenicol. It widely used for the treatment of infectious diseases in humans and veterinary medicine. Recently, it has found as a feed additive for animal-breeding. However, administration of TAP has side effects on body organs especially bone marrow and testicular tissues have been proven scientifically. Aim of work: The aim of the current study is to mitigate thiophenicol’s side effects by using some antioxidant as spirulina and gensing. Material & Methods: One hundred and twenty eight male albino rats were divided into 8 groups for administrating with all possible combinations of the treatments consist of: control, thiophenicol (TAP), spirulina (SP), gensing (Gn) and their combinations. The rats were sacrificed after 14 days of treatments. The bone marrow and testis were fixed, and paraffin sections were stained. Results: The sole TAP treated rats showed a reduction in spermatogenesis and infiltrative inflammatory cells in the thicking intersitium between the seminefrous tubules of testis. In addition, single TAP treatments decreased erythropoiesis and increased the Myeliod:Erythriod ratio of bone marrow.TAP treated groups with SP and GN showed a slight change in bone marrow and testicular tissue compared with TAP group. The antioxidants groups have the normal histological structure similar to those of the control group. Conclusion: We concluded that spirulina and gensing have a potential positive action in mitigating the side effects of thiophenicol on bone marrow and testis of rats.