Labile soil organic matter (SOM) is a small fraction of total SOM that rapidly undergoes chemical, physical, and/or biological change. Despite the small proportion of SOM, we know this biologically active fraction of SOM is disproportionately important soil ecosystem services. Here I will talk about what is labile SOM, discuss links to soil health (i.e. ecosystem services), describe ways to measure it and use it for prediction, and what happens when we add labile carbon to Iowa farm fields.