Although microdialysis has been available for almost two decades, it has only recently been applied in investigations of adipose tissue. The microdialysis technique enables continuous sampling of metabolites and other small molecules from the extracellular space of subcutaneous adipose tissue from intact animals or man, and the exposure of this compartment locally to metabolically active agents without causing generalized effects. To date, the method has been used to measure the steady-state interstitial levels of metabolites and to investigate the regulation of lipolysis and carbohydrate metabolism in situ in subcutaneous adipose tissue. Apart from a great potential for experimental research, the microdialysis method offers several new possibilities for clinical investigation. Because microdialysis probes are easy to implant and cause little discomfort, they may be used for continuous monitoring of glucose and glycerol (lipolysis index) in the treatment of diabetes, obesity and other disorders characterized by disturbances in lipid and carbohydrate metabolism.