Drought-induced vegetation mortality is increasingly observed across biomes and is linked to rising temperatures, droughts, and biotic stressors. The mechanisms behind plant mortality remain poorly understood, with debates focusing on carbon starvation (reduced carbon supply due to prolonged negative carbohydrate balance) and hydraulic failure (desiccation from failed water transport). This review integrates carbon metabolism with hydraulic failure evidence, highlighting their interdependence and uncertainties. Drought reduces plant growth before photosynthesis, leading to a surplus of non-structural carbohydrates (NSC). However, prolonged drought can deplete NSC as it is used for maintenance and metabolism. Carbon starvation occurs when NSC is insufficient to support respiration, growth, and defense. Hydraulic failure, caused by cavitation in xylem, can also lead to mortality. These processes are interconnected, with water stress affecting NSC transport, metabolism, and defense, accelerating carbon starvation and increasing vulnerability to biotic agents. Carbon starvation is supported by observations of elevated NSC in stressed plants and reduced photosynthesis. Molecular evidence shows that stress triggers changes in carbohydrate metabolism, including increased storage and reduced growth. NSC is crucial for maintaining turgor and photosynthesis, and its depletion leads to mortality. Hydraulic failure, involving xylem cavitation, can exacerbate carbon starvation by reducing water availability and increasing the risk of turgor loss. The interplay between carbon metabolism and hydraulics is complex, with drought affecting both processes. Isohydric species, which tightly regulate water potential, experience greater cavitation and refilling than anisohydric species. This highlights the importance of hydraulic safety margins and the coupling of carbon starvation and hydraulic failure in mortality. Future research should focus on quantifying the states and fluxes of carbon and hydraulic processes in dying plants, understanding the minimum NSC required for survival, and exploring the interactions between plant hydraulics and carbon metabolism at the whole-plant scale. Experimental approaches, including manipulations of water, temperature, and CO₂, and field studies, are needed to clarify the mechanisms of mortality. Integrating ecological, physiological, and molecular knowledge will improve understanding of plant mortality and survival under environmental stress.Drought-induced vegetation mortality is increasingly observed across biomes and is linked to rising temperatures, droughts, and biotic stressors. The mechanisms behind plant mortality remain poorly understood, with debates focusing on carbon starvation (reduced carbon supply due to prolonged negative carbohydrate balance) and hydraulic failure (desiccation from failed water transport). This review integrates carbon metabolism with hydraulic failure evidence, highlighting their interdependence and uncertainties. Drought reduces plant growth before photosynthesis, leading to a surplus of non-structural carbohydrates (NSC). However, prolonged drought can deplete NSC as it is used for maintenance and metabolism. Carbon starvation occurs when NSC is insufficient to support respiration, growth, and defense. Hydraulic failure, caused by cavitation in xylem, can also lead to mortality. These processes are interconnected, with water stress affecting NSC transport, metabolism, and defense, accelerating carbon starvation and increasing vulnerability to biotic agents. Carbon starvation is supported by observations of elevated NSC in stressed plants and reduced photosynthesis. Molecular evidence shows that stress triggers changes in carbohydrate metabolism, including increased storage and reduced growth. NSC is crucial for maintaining turgor and photosynthesis, and its depletion leads to mortality. Hydraulic failure, involving xylem cavitation, can exacerbate carbon starvation by reducing water availability and increasing the risk of turgor loss. The interplay between carbon metabolism and hydraulics is complex, with drought affecting both processes. Isohydric species, which tightly regulate water potential, experience greater cavitation and refilling than anisohydric species. This highlights the importance of hydraulic safety margins and the coupling of carbon starvation and hydraulic failure in mortality. Future research should focus on quantifying the states and fluxes of carbon and hydraulic processes in dying plants, understanding the minimum NSC required for survival, and exploring the interactions between plant hydraulics and carbon metabolism at the whole-plant scale. Experimental approaches, including manipulations of water, temperature, and CO₂, and field studies, are needed to clarify the mechanisms of mortality. Integrating ecological, physiological, and molecular knowledge will improve understanding of plant mortality and survival under environmental stress.