Thirty-six Sprague Dawley male rats were housed in individual cages and randomly divided into six groups: control, copper sulfate (Cu; 500 ppm body weight (BW)/day), flunixin meglumine (FM; 2.2 ppm BW/day), chrysin (chrysin; 50 ppm BW/day), copper sulfate + FM (Cu + FM; 500 ppm BW/day of copper sulfate and 2.2 ppm BW/day of FM), and copper sulfate + chrysin (Cu + Chrysin; 500 ppm BW/day of copper sulfate and 50 ppm BW/day of chrysin). Feed intake (FI) in the Cu + Chrysin group significantly increased in comparison with that of the Cu group (P < 0.01). Cu excess significantly increased malondialdehyde, indicating oxidative stress. Chrysin and FM administration significantly decreased malondialdehyde levels and increased the superoxide dismutase and catalase activities in the liver and kidney tissues (P < 0.001). Serum TNF-a levels were significantly lower in the Cu + FM and Cu + Chrysin groups in comparison to the Cu group (P < 0.001). It was seen that FM and chrysin treatments alleviated degeneration, necrosis, and apoptosis in the liver and kidney tissues of the Cu-treated rats. Chrysin appeared to ameliorate the adverse effects on FI and liver and kidney tissues by scavenging where the free radicals are located and increasing the activity of antioxidants.