The ability to couple high-resolution specimen imaging with chemical state analysis allows problems in biology and medicine to be approached in a novel and powerful way. Element specific chemical state analysis can be performed at tunable synchrotron X-ray sources through core level absorption spectroscopy, and a number of methods have been developed to routinely use this technique at the microscopic scale relevant to cellular phenomena. A diverse range of biological specimens has been studied in the MEPHISTO spectromicroscope, and some results are discussed here. The examples are used to illustrate the ability of spectromicroscopy to obtain certain specific results. such as semi-quantitative element detection, and chemical state elucidation or mapping. Essential practical considerations are also emphasized, including sample preparation, the sensitivity of absorption spectroscopy, interferences between elements, and the use of complementary sample analyses. (C) 2001 Elsevier Science B.V. All rights reserved.