Numerous studies have demonstrated that molecules derived from natural sources such as plants, microalgae, and food products exhibit significant therapeutic potential. This positions them as effective candidates for both primary and adjunctive treatment strategies across a broad spectrum of human diseases. Their efficacy is attributed to the presence of multiple bioactive constituents, their natural abundance, and a favorable safety profile, characterized by a low incidence of adverse effects. In various forms, whether crude, partitioned, or fractionated, these extracts offer pharmacological advantages over isolated compounds, owing to their pleiotropic mechanisms of action and the synergistic interactions among their components. Nevertheless, the clinical translation of these natural bioactives remains constrained by limitations such as low bioavailability, poor aqueous solubility, and chemical instability, which hinder the extrapolation of in vitro and in vivo outcomes to clinical practice. In response to these challenges, the development of nanotechnology-based delivery systems has emerged as a promising strategy to enhance their therapeutic performance. Green nanoparticles, synthesized from natural products, represent innovative platforms capable of improving stability, bioavailability, selectivity, and systemic distribution of phytochemicals. These nanostructures have shown considerable potential in diverse biomedical applications, including antimicrobial activity, anti-inflammatory effects, oncology, nephroprotection, and hepatoprotection. Consequently, the integration of phytotherapy with nanotechnology not only offers more efficacious and safer therapeutic alternatives for the management of chronic diseases but also aligns with the Sustainable Development Goals (SDGs) outlined in the 2030 Agenda, particularly those concerning health and well-being (SDG 3), industry, innovation, and infrastructure (SDG 9), and responsible consumption and production (SDG 12). This integrative approach supports the advancement of more accessible, sustainable, and technologically driven health care solutions.