Objective To ohserve the rat myocardial damage induced by citreoviridin(CIT)in the status of combined selenium and protein deficiency.Methods According to 2×2 factorial design,forty 4-week-old healthy Wistar rats were randomly divided into four groups.i.e.combined selenium and protein adequate with no CIT and with some CIT groups(Se+Pro+CIT-.Se+Pro+CiT+),combined selenium and protein deficiency with no CIT and with some CIT groups(Se-Pro-CIT-,Se-Pro-CIT+).The numbers of male and female were fifty-fifty.Theserats were fed with combined selenium and protein adequate and combined selenium and protein deficiency fodder until the 16th week. Cardiac toxicity of CIT was evaluated by general state of health, heart weight index, myocardial pathological change, the levels of selenium and the activities of glutathion peroxidase (GSH-Px) and creatine kinase (CK) in serum, and the activity of superoxide dismutase(SOD) of myocardium. Results The interaction effects of combined selenium and protein deficiency and adequate CIT on body weight, serum levels of selenium and albumin, heart weight index, the activities of CK and GSH-Px in serum and SOD of myocardium were statistically not significant(F= 0.000, 1.210, 0.625, 0.981, 2.785, 0.074, 0.001, all P> 0.05). The main effects of combined selenium and protein on the levels of serum selenium and albumin, heart weight index and the activity of GSH-Px in serum were statistically significant(F = 507.698, 87.734, 4.201, 109.389, all P < 0.05). The main effects of CIT on body weight, the levels of serum selenium and albumin, heart weight index and the activity of CK in serum were statistically significant(F = 10.929, 4.371, 26.108, 24.844, 4.439, all P < 0.05). The mean levels of serum selenium of Se-Pro- groups [(70.4 ± 40.0), (87.7 ± 59.6 )μg/L] were lower than those of Se+Pro+ groups [(446.1 ± 74.8),(502.1 ± 39.2)μg/L, all P < 0.05]. The mean levels of serum albumin of Se-Pro- groups [(34.36 ± 1.28 ), (33.38 ±2.48)g/L] were lower than those of Se+Pro+ groups[(40.69 ± 1.30), (38.71 ± 2.15)g/L, all P < 0.05]. The mean levels of heart weight index of CIT+ groups[(4.14 ± 0.36) × 10-3, (4.39 ± 0.53) x 10-3] were higher than those of CIT-groups[(3.56 ± 0.26) x 10-3, (3.80 ± 0.28) x 10-3, all P < 0.05] respectively at the same levels of selenium and protein. The mean levels of CK in serum of Se-Pro-CIT+ group[(2.54 ± 0.56)kU/L] was lower than that of Se-Pro-CIT- group [(3.37 ± 0.67 )kU/L, P < 0.05]. The mean levels of activity of GSH-Px in serum of Se-Progroups[(408.1 ± 412.6), (510.5 ± 392.0)U/L] were lower than those of Se+Pro+ groups[(1667.8 ± 102.2),(1731.5 ± 144.4)U/L, all P < 0.05]. In Se+Pro+CIT+ group, there was part of intercalary disc of cardiac myocytes fragmented;the conjunctions between myoeytes were broken;in some region, cardiac myocytes became edematous,even dissolved. In Se-Pro-CIT- group, the change of cardiac myocytes membrane structures was not obvious;filament structure was disappeared around nucleus;deposition of mass floccule could be seen. In Se-Pro-CIT+ group,the structure of sarcomeres was not obvious;mitochondrial cristae was loosened;cavities in myocytes could be seen occasionally;there were lots of disseminated sareoplasmic reticulum extending. Conclusions .CIT is the main risk factor in inducing myocardial damage. The deficiency of combined selenium and protein can aggravate the damage,but its independent pathogenic effect is weak.