Trehalose is a naturally occurring, non-reducing disaccharide with diverse roles in cellular protection and therapeutic applications. It functions as an osmoprotectant, chemical chaperone, free radical scavenger, carbon source, virulence factor, and metabolic regulator. This review highlights trehalose's role in maintaining cellular homeostasis under stress and its involvement in bacterial and fungal virulence. Trehalose is synthesized through multiple pathways in various organisms and is degraded by specific enzymes. It protects cells against desiccation, oxidative stress, and other environmental stresses by stabilizing proteins, preventing aggregation, and maintaining cellular structure. Trehalose also acts as a free radical scavenger, reducing oxidative damage and enhancing antioxidant defenses. It plays a regulatory role in metabolic processes, influencing glucose metabolism, autophagy, and gene expression. Trehalose has neuroprotective effects by inhibiting protein aggregation and activating autophagy. It is also involved in glucose homeostasis, improving insulin sensitivity and reducing inflammation. Trehalose's role in pathogenicity includes aiding bacterial and fungal survival in host environments and contributing to virulence. Trehalose may serve as a therapeutic agent for neurodegenerative diseases, diabetes, and other conditions. Additionally, trehalose has potential applications in antifungal and antibacterial therapies due to its role in pathogen survival and virulence. Trehalose is used in various industries for its stabilizing properties, including food, cosmetics, and pharmaceuticals. Its potential as a drug and its role in pathogenicity make it an important area of research for developing new therapeutic strategies.Trehalose is a naturally occurring, non-reducing disaccharide with diverse roles in cellular protection and therapeutic applications. It functions as an osmoprotectant, chemical chaperone, free radical scavenger, carbon source, virulence factor, and metabolic regulator. This review highlights trehalose's role in maintaining cellular homeostasis under stress and its involvement in bacterial and fungal virulence. Trehalose is synthesized through multiple pathways in various organisms and is degraded by specific enzymes. It protects cells against desiccation, oxidative stress, and other environmental stresses by stabilizing proteins, preventing aggregation, and maintaining cellular structure. Trehalose also acts as a free radical scavenger, reducing oxidative damage and enhancing antioxidant defenses. It plays a regulatory role in metabolic processes, influencing glucose metabolism, autophagy, and gene expression. Trehalose has neuroprotective effects by inhibiting protein aggregation and activating autophagy. It is also involved in glucose homeostasis, improving insulin sensitivity and reducing inflammation. Trehalose's role in pathogenicity includes aiding bacterial and fungal survival in host environments and contributing to virulence. Trehalose may serve as a therapeutic agent for neurodegenerative diseases, diabetes, and other conditions. Additionally, trehalose has potential applications in antifungal and antibacterial therapies due to its role in pathogen survival and virulence. Trehalose is used in various industries for its stabilizing properties, including food, cosmetics, and pharmaceuticals. Its potential as a drug and its role in pathogenicity make it an important area of research for developing new therapeutic strategies.