Background <p><i>Polygonatum sibiricum</i>, a highly esteemed traditional tonic in China, is a typical dual-purpose food-medicine resource with deep roots in culinary traditions. It is widely recognized for its efficacy in tonifying qi, nourishing yin, bolstering the spleen, moistening the lungs, and benefiting the kidneys—properties attributed to its rich array of bioactive constituents, primarily polysaccharides, saponins, and flavonoids. These bioactive molecules exhibit significant biological activities, including antioxidant, immune-modulating, and metabolic-regulating effects, which are exerted through interactions with diverse molecular targets and the regulation of intricate signaling pathways. This context lays the foundation for exploring the scientific basis of <i>Polygonatum sibiricum’s</i> traditional and potential functional applications.</p> Main body <p>This review conducts a systematic and in-depth investigation into recent advancements related to the key bioactive components (primarily polysaccharides, saponins, and flavonoids) of <i>Polygonatum sibiricum</i>, covering cutting-edge techniques and progress in their extraction, separation, and structural characterization—critical steps for deciphering their biological functions; at the same time, it places special emphasis on how processing methodologies (including traditional and modern preparation methods) alter the qualitative and quantitative profiles of these bioactive compounds and directly influence their resultant biological activities, addressing the key gap between traditional processing practices and modern scientific validation. Furthermore, the review meticulously dissects the distinct functional mechanisms of each major bioactive component: polysaccharides are focused on for their immune-regulatory functions, such as modulating immune cell activity, cytokine secretion, and immune signaling pathways; saponins are highlighted for their metabolic-regulating prowess, including their effects on glucose and lipid metabolism and potential in addressing metabolic disorders; and flavonoids are emphasized for their potent antioxidant properties, such as scavenging free radicals, inhibiting oxidative stress-related enzymes, and protecting cells from oxidative damage.</p> Conclusion <p>By synthesizing the latest research findings and highlighting emerging insights into <i>Polygonatum sibiricum’s</i> bioactive components, this review aims to establish a robust scientific foundation and provide strategic references for two key objectives—one being advancing innovative research on <i>Polygonatum sibiricum</i>, particularly in clarifying the links between its chemical composition, processing, and biological activity, and the other being facilitating the development of <i>Polygonatum sibiricum</i> as a high-value functional food ingredient, which ultimately unlocks its full molecular potential for applications in nutrition, health promotion, and related industries.</p>