The SEM/EDS is a valuable tool in the pharmaceutical industry for aiding in the identification of isolated particles. It is a part of our systematic approach which proceeds from lower magnification techniques, e.g., stereomicroscope, to higher magnification techniques, eg., polarized light microscopy, and finally to the high magnification of SEM/EDS. Particles associated with pharmaceutical product rejects are due to a variety of sources, often due to the ubiquitous use of some materials, e.g., stainless steel alloys, in the manufacturing arena. Our particles of interest range in size from submicron to ≥ 50 μm (visible with the unaided eye), appearing in numerous shapes and/or colors. Any particles contained in a drug product or associated with the package are objectionable. Detection during production operations and/or during the terminal 100% inspection prior to market release will cause product rejection. In any case, foreign particles are not tolerated. Their identification leads to their source and thus proper corrective action.