Citrus refers to a genus of flowering shrubs and trees belonging to the Rutaceae family. Citrus fruits are among the
most widely cultivated and consumed fruits globally, serving as important sources of nutrients and nutraceuticals.
Major species include Citrus sinensis (sweet orange), Citrus limon (lemon), Citrus paradisi (grapefruit), Citrus medica
(citron), Citrus aurantium (sour orange), Citrus maxima (pummelo), Citrus reticulata (tangerine), and Citrus
clementina (clementine). These fruits are valued not only for their refreshing juices but also for their bioactive-rich
by-products (peels, pulp, and seeds), which exhibit diverse pharmacological properties. This review was conducted
through a structured literature search of major scientific databases, including Scopus, Web of Science, PubMed, and
Google Scholar, covering publications from 2000 to 2024. Keywords such as “citrus phytochemicals,” “citrus
flavonoids,” “limonoids,” “citrus essential oils,” “bioactivity,” and “toxicity” were used. Peer-reviewed experimental,
clinical, and review articles published in English were included, with emphasis on studies addressing both health
benefits and toxicological outcomes of citrus-derived compounds. Reported biological activities include antidiabetic,
anticancer, antihypertensive, antihypercholesterolemic, anti-obesity, antiviral, antifungal, antibacterial, anti-
inflammatory, and antioxidant effects. These health-promoting properties are largely attributed to the diverse
phytoconstituents present in citrus fruits, including flavonoids, limonoids, carotenoids, coumarins, and essential oils.
However, despite these benefits, emerging evidence indicates that excessive intake or high concentrations of certain
citrus phytochemicals may elicit toxic effects, highlighting important safety concerns. This review critically examines
both the nutraceutical benefits and potential toxicities of citrus phytoconstituents, emphasizing their dual biological
roles. Furthermore, it underscores the need for mechanistic and dose–response studies to better define toxicity
pathways and establish safe consumption thresholds