Arthropod predators and parasitism, traditionally considered carnivorous, often rely on plant-derived food sources at various stages of their life cycles, influencing their life-history parameters. Plant guttation, a largely unexplored food source, consists of exudates secreted through hydathodes on leaf surfaces, containing a diverse array of organic and inorganic compounds. While plant guttation can serve as a valuable nutritional resource for insects, it can also harbour pesticide residues and microorganisms, influencing insect communities and interactions. Additionally, plants utilize guttation as a mechanism for defence against herbivores and pathogens by accumulating toxic compounds. This review explores the nutritional value of plant guttation for insects, its role in pesticide residue analysis, and its significance in plant defence mechanisms. Understanding the complexities of plant guttation is crucial for maximizing its potential benefits in agricultural and non-agricultural ecosystems, highlighting the need for integrated approaches to enhance biological control and ecological sustainability.