Various studies have reported that Noni shows various health effects. This study aimed to assess the ability of Noni fruit extract to serve as a single active functional ingredient for the alleviation of hangover symptoms in Sprague Dawley rats and healthy subjects in a single-dose, randomized, double-blind, crossover, placebo-controlled study. The rats were orally administered Noni fruit extract at 50 or 100 mg per kg body weight (B.W.) and HOVENIA. The blood ethanol (EtOH) and acetaldehyde concentrations were significantly lower in the 100 mg per kg B.W. group than in the EtOH group. Alcohol dehydrogenase and aldehyde dehydrogenase activity tended to increase in the 100 mg kg-1 B.W. group. In the human study, 30 subjects received either a placebo or Noni fruit extract (1 g). The Noni fruit extract group showed significantly faster time point at which the maximum concentration (Tmax) of alcohol than in the placebo group. In addition, blood acetaldehyde levels and diarrhea at 40 and 720 min after alcohol intake and the area under the curve between 40 and 60 min of acetaldehyde were significantly decreased in the Noni fruit extract group compared to the placebo group. According to the QUalitative INteraction Trees, subjects who were ≤36 years old who consumed more alcohol (>15 drinks per week) and had a higher total hangover score (>27.5 and 33) presented significantly lower blood acetaldehyde levels and less severe hangover symptoms. These results indicate that Noni fruit extract has the potential to improve hangover symptoms by decreasing alcohol and acetaldehyde levels.