The toxicity of hydroxychloroquine (HCQ) can impact the function of vital organs, leading to ocular and cardiovascular damage. This study aims to evaluate the toxicity of HCQ through electrocorticographic evaluation and blood biochemical parameters in Wistar rats. The animals received a dose of HCQ of 350 mg/kg via gavage every 12 hours for periods of 24, 48, 72 and 96 hours, with each group consisting of n = 9. After treatment, the animals underwent surgery to implant electrodes in the motor cortex region and subsequently underwent bipolar electrocorticography. The electrodes for acquiring electrocardiographic recordings were fixed in the D II position and blood samples were analyzed for liver and kidney function. The results demonstrated that high doses of HCQ altered electrocorticographic features, decreased cardiac activity throughout treatment, and significantly elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. However, assessment of renal function, as indicated by serum creatinine levels, revealed no significant changes. These results suggest that exposure to high doses of HCQ in rats may disrupt the structures and functions of vital organs.