Across different cultures around the globe, human beings have historically depended largely on medicinal plants for managing diseases that have hitherto threatened their optimal health, survival, and longevity. Evidently, the health-derived benefits of medicinal plants can be strongly attributed to the presence of secondary metabolites, particularly polyphenols. The health-promoting effects of Sorghum bicolor supplement Jobelyn® (SBSJ) —a unique supplement derived from the leaf sheaths of a West African variety of Sorghum bicolor (L.) Moench—have also been ascribed to its high levels of polyphenols. This review seeks to gather and synthesize findings from various experimental and clinical studies on the health benefits of SBSJ in arthritis, cancer, chronic viral infections, stroke, anaemia, and aging. SBSJ has been reported to contain potent bioactive polyphenolic compounds with polyvalent biological activities, including antioxidant, anti-inflammatory, immunomodulatory, chemopreventive, and neuroprotective activities. Moreover, the probable benefits of SBSJ in chronic viral infections (e.g., HIV/AIDS and COVID-19) have been attributed to its potent anti-inflammatory and immunomodulatory activities. As this supplement is increasingly becoming one of the fastest-selling herbal medicines in Nigeria, there is a need for more robust studies (including clinical trials) in order to replicate and validate the prior insights gleaned from experimental studies.