Abstract: In this study, the rheological properties of composite flour and their guar meal blends were studied by farinography. The water absorption percent, arrival time, development time, dough stability, mixing tolerance, ash, protein, falling number, baking strength, index of swelling and extensibility were estimated. The effect of feeding guar seeds powder on liver enzymes (GOT and GPT) and kidney functions (urea and creatinine) of rats were investigated. The results showed that diets with 5% guar seeds powder had the best effect on GOT (17.7 U L-1), GPT (22.2 U L-1), urea (26.0 mg dL-1) and creatinine (0.83 mg dL-1). Histopathological studies were also carried out in the kidney and liver of the albino rats.