Abstract Elderberry (Sambucus nigra) is rich in anthocyanins and polyphenols and has long been used for respiratory health. This review synthesizes mechanistic and clinical evidence on elderberry as a nutritional adjunct for upper respiratory tract infections (URTI), influenza, the common cold, COVID-19/Long COVID, allergic airway diseases, rhinosinusitis, and pharyngitis, and outlines rational combinations with co-nutrients. Methods:We narratively integrated randomized controlled trials, meta-analyses, and in-vitro/in-vivo studies evaluating antiviral, anti-inflammatory, antioxidant, and immunomodulatory actions. Clinical endpoints included illness duration, symptom severity, medication use, and surrogate markers of inflammation/oxidative stress. We also appraised complementary roles of quercetin, bromelain, elastin peptides, mulberry leaf polyphenols, vitamin C, vitamin D, and zinc. Results:Elderberry exhibits multi-target mechanisms: it interferes with viral glycoprotein-host receptor interactions and early replication; down-regulates inflammatory signaling (e.g., NF-κB) and cytokines (TNF-α, IL-6); scavenges reactive species and activates Nrf2-dependent defenses (GSH, SOD, CAT); and enhances mucosal immunity (sIgA) and innate cell activity (macrophages, NK cells). Across RCTs in influenza/URTI, elderberry consistently shortened illness by ~1-2 days and reduced symptom scores, with some trials reporting decreased rescue medication. Evidence for COVID-19 is indirect - supported by anti-coronavirus in-vitro data and polyphenol-based mechanistic plausibility - but lacks large, definitive clinical trials. For allergic rhinitis/asthma and rhinosinusitis/pharyngitis, data are mainly mechanistic or small-scale, suggesting potential benefits in nasal congestion, throat pain, cough, and mucosal recovery. Co-nutrients provide complementary coverage across viral entry/replication, inflammatory amplification, oxidative stress, mucus rheology, and epithelial barrier repair. Conclusions:Elderberry is a plausible, evidence-supported adjunct for respiratory infections, with the strongest clinical signal in influenza and URTI. Early-stage use and deployment in susceptible populations may yield clinically meaningful symptom relief and faster recovery. Combination protocols with quercetin, bromelain, elastin peptides, mulberry leaf, vitamin C/D, and zinc are mechanistically coherent and may broaden benefits. Rigorous, adequately powered trials are still needed for COVID-19 and allergic/ENT indications. Elderberry should complement - rather than replace - standard medical care.