Red cabbage dye (RCD) and its inhibitory effect on the corrosion of mild steel in 1N HCl and 1N H3PO4 was investigated by weight loss and electrochemical methods. RCD was a good inhibitor for mild steel corrosion in acid solutions, affecting anodic and cathodic reactions. The inhibition efficiency increased with RCD concentrations, with more pronounced effects observed in HCl. The effect of temperature on corrosion inhibition was studied and kinetic activation parameters were calculated and discussed. The inhibition mechanism of RCD on the mild steel surface was related to the dye make up and behavior in acid solutions.