Spirulina is one of the most commonly used dietary supplements in humans, aquaculture, aquarium, and recently in poultry industries and gained more attention to be used as a nutritional and therapeutic strategy. The present study has been carried out to investigate the effect of oral supplementation of Spirulina platensis in alleviating the hepatotoxic effect of diclofenac sodium through evaluating the hematological, biochemical, antioxidant parameters as well as immunological and histopathological studies. One hundred broiler chicks were divided into four groups (25 per each). The first group was fed on basal diet and treated with propylene glycol (2.5 mg/kg, i.m) (Control negative). The secondgroup was fed on basal diet and injected with diclofenac sodium at dose (2.5 mg/kg.b.wt., i.m) (Control positive). The third group was injected with diclofenac sodium and then concurrently supplemented with Spirulina at dose (10 gm/kg in their diet). The fourth group was fed on Spirulina two weeks before injection of diclofenac sodium at dose (2.5 mg/kg, i.m). Haematological data revealed that diclofenac-treated chicks showed normocytic normochromic anemia, significant leucopenia and decrease the absolute number of heterophils and lymphocytes. Significant increase in serum biochemical parameters related to liver injury such as AST and ALP, total cholesterol and significant decrease in the levels of serum total proteins and albumin. Significant increase in uric acid level was also noticed. Furthermore, significant increase of oxidative damage biomarkers such as MDA and NO and significant decrease of the antioxidant enzymes as CAT, SOD and TAC. Moreover, diclofenac sodium has immunosuppressive effect through depressed phagocytic activity, phagocytic index and marked decrease in the titer of antibodies formed in chicks against Newcastle disease. Histopathological findings marked hepatic tissue damage due to gouty tophi lesions accompanied with presence of multifocal necrotic areas. Oral supplementation of Spirulina markedly decrease the histopathological alteration on preventive basis. Therefore, Spirulina supplementation markedly alleviated the deteriorating effects of diclofenac sodium-induced hepatotoxicity which mimics the gouty lesions in birds either on therapeutic or preventive regimes.