Smoking is associated with an increased incidence of numerous cancers and other degenerative diseases. It has been suggested that high consumption of fruits and vegetables may give some protection. Especially carrot is the most important source of dietary β-carotene. Therefore, the objective of this study is to investigate whether carrot juice supplementation to smokers have different or superior effect of compared to the effect supplementing purified β-carotene. The study was conducted in a randomized and placebo-controlled design, after a depletion period of 14 days, 48 smokers were supplemented either carrot juice (n = 18), purified β-carotene (n = 16) or placebo (n = 14). Each group was supplemented for 8 weeks with approximately 20.49 ㎎ of β-carotene/day and 1.2 ㎎ of vitamin C/day, as carrot juice (300 ㎖/day) or purified β-carotene (1 capsule/day). Plasma vitamin C, vitamin E and β-carotene level were significantly increased after carrot juice and β-carotene supplementation. These results suggest that carrot juice containing β-carotene or β-carotene itself have similar antioxidative potentials by increasing the antioxidant potential in smokers. Therefore, we suggest moderate dose of vitamin supplementation (amount of two servings of vegetable intake) may help to replenish the decreased oxidative stress levels in smokers.