Emetic foodborne toxins (bacterial enterotoxins, mycotoxins like DON/ZEA, marine toxins, cereulide, T-2 toxin, domoic acid, and biogenic amines such as histamine) cause acute gastrointestinal reactions and chronic systemic pathologies. This review outlines their activation of the brainstem's area postrema (AP) via intestinal barrier disruption, dysbiosis, vagus nerve stimulation, or direct central penetration. Acute exposure induces anorexia/defense responses through AP/NTS receptor pathways (GLP-1R, CCK, PYY, ghrelin, GDF15-GFRAL, 5-HT3). Chronic exposure impairs the AP-hypothalamus-locus coeruleus (LC) pathway, causing neuropsychiatric disorders, cachexia-like metabolic reprogramming, and multi-organ dysfunction. The gut microbiota play pivotal roles in toxin metabolism, bioactivation, and detoxification; microbial dysbiosis and LPS translocation amplify systemic inflammation. The elderly, immunocompromised individuals, and patients with comorbidities are particularly vulnerable due to weakened barriers, immunosenescence, and polypharmacy. This review elucidates the toxin-induced acute-to-chronic cascade via the gut-brain-neuro-metabolic network, discusses current limitations and future directions, and provides a theoretical basis for understanding chronic pathogenic mechanisms and complex comorbidities.