The aim of this study was to determine whether a single local probucol administration could suppress neointimal formation in balloon-injured rat carotid artery. Rats were divided into four groups; (i) rats receiving no probucol (control group); (ii) rats receiving topical application of 50 mg probucol at the time of ballooning (p-top group); (iii) rats fed chow containing 1% probucol (p-fed group; (iv) rats receiving both topical application of 50 mg probucol and chow containing 1% probucol (p-top/fed group). Although serum total cholesterol levels did not significantly differ between the control and the p-top groups at two weeks after balloon injury, the p-top group had a smaller intimal/medial ratio or intimal area than the control group (0.97 +/- 0.11 vs. 0.53 +/- 0.08 or 0.15 +/- 0.02 mm2 vs. 0.08 +/- 0.02 mm2 respectively, P < 0.01). Neointimal formation was suppressed to a similar extent in the p-fed group, in which serum total cholesterol level was approximately 40% lower than that in the control group. Thus, a single local delivery of probucol can suppress neointimal formation in balloon-injured rat carotid artery without altering serum lipid level.