Heavy drinking causes hangover symptoms, because the action of alcohol dehydrogenase forms acetaldehyde, which is metabolized by acetaldehyde dehydrogenase into acetate. Red ginseng shows positive effects on alcohol metabolism in animal studies. We investigated the effects of red ginseng on relieving alcohol and hangover symptoms in 25 healthy men in a randomized crossover study. At each visit (0, 1, and 2 weeks), the subjects drank 100 mL whiskey (40% alcohol) and either 100 mL water or 100 mL of a 0.321 mg mL(-1) red ginseng anti-hangover drink (RGD). We took blood samples periodically until 240 min after alcohol consumption, and we investigated the blood profiles, alcohol levels, and acetaldehyde levels. We also measured anthropometric parameters, expiratory air-alcohol levels, and hangover symptoms. The plasma alcohol concentrations within the RGD group were significantly lower than those within the placebo group after 30 min (p = 0.002), 45 min (p = 0.016), and 60 min (p = 0.009); the areas under the response curves revealed a positive effect of RGD (p = 0.051). Furthermore, the expiratory alcohol concentration was significantly lower after 30 min (p = 0.005) and 60 min (p = 0.065), and the areas under the response curves (p = 0.058) likewise revealed a positive effect of RGD. The plasma acetaldehyde level was significantly elevated at 120 min (p = 0.020), but the areas under the response curves showed a similar trend (p = 0.054). While the plasma acetaldehyde concentration slightly increased, the RGD showed positive effects on hangover symptoms. Considering the reduction of plasma alcohol levels, expiratory concentrations, and hangover severity, we conclude that red ginseng relieves the symptoms of alcohol hangover.