Nanodrugs hold great promise for targeted therapies, but their potential for cytotoxicity remains a major area of concern, threatening both patient safety and clinical translation. In this systematic review, we conducted a systematic investigation of nanotoxicity studies-identified through an AI-assisted screening procedure using Scopus, PubMed, and Elicit AI-to establish the molecular determinants of nanodrug-induced cytotoxicity. Our findings reveal three dominant and linked mechanisms that consistently act in a range of nanomaterials: oxidative stress, inflammatory signaling, and lysosomal disruption. Key nanomaterial properties like chemical structure, size, shape, surface charge, tendency to aggregate, and biocorona formation control these pathways, modulating cellular uptake, reactive oxygen species generation, cytokine release, and subcellular injury. Notably, the most frequent mechanism was oxidative stress, which often initiated downstream inflammatory and apoptotic signaling. By linking these toxicity pathways with particular nanoparticle characteristics, our review presents necessary guidelines for safer, more biocompatible nanodrug formulation design. This extensive framework acknowledges the imperative necessity for mechanistic toxicity assessment in nanopharmaceutical design and underscores the strength of AI tools in driving systematic toxicology studies.