Characterising changes in the plant metabolome is central to understanding adaptive responses to environmental change. New and improved quantitative and qualitative technologies have enabled the characterisation of plant metabolism at unprecedented scales and precision. New frontiers have therefore emerged for improving our understanding of the adaptability of plant metabolic networks. However, despite these advances, outcomes for 'in field' plant management remain largely based on subsets of plant metabolism due to broader scale network complexity. The synthesis and occurrence of polyols offer considerable promise as bioindicators of plant health and biomarkers for use as selective traits for plant improvement. Polyols are polyohydroxy compounds that may be either open chain (acyclic) alditols or cyclic compounds (cyclohexan-hexols), usually termed cyclitols or inositols. Here we highlight the functions of polyols in stress acclimation or amelioration and as sinks for carbon and indicate their potential for the development of integrated measures of plant function using new technologies in 21st century plant breeding.