Noni juice is a globally popular health beverage that originates from the tropics. Traditional Tahitian healers believe the noni plant to be useful for a wide range of maladies, and noni juice consumers throughout the world have similar perceptions. Nevertheless, human clinical trials are necessary for an understanding of what the health benefits of noni juice truly are. A review of published human intervention studies suggest that noni juice may provide protection against tobacco smoke-induced DNA damage, blood lipid and homocysteine elevation, and systemic inflammation. Human interventions studies also suggest that noni juice may improve joint health, increase physical endurance, increase immune activity, inhibit glycation of proteins, aid weight management, help maintain bone health in women, help maintain normal blood pressure, and improve gum health. Further, these studies point to noni juice possessing notable antioxidant activity, more so than the other fruit juices that served as placebos. It is this antioxidant effect, and its interaction with the immune system and inflammation pathways, that may account for many of the observed health benefits of noni juice. However, the existing evidence does have some limitations in its application to noni juice products in general as all the peer-reviewed human interventions studies to-date have involved only one source of French Polynesian noni juice. Geographical factors and variations in processing methods are known to produce commercial noni juice products with divergent phytochemical and nutrient compositions. Therefore, other sources of noni products may have different toxicological and pharmacological profiles.