We have used the Stewart approach to typical acute and compensated acid-base disorders here. Dedicated software developed by the author is available with this article and will be of help to anyone considering analyzing his or her own patients using the Stewart approach. The Stewart approach shares analytical steps with the more traditional Siggard-Andersen method, and in most cases the two methods arrive at the same therapeutic solutions. The Stewart approach is, however, more than merely a biophysical appendix to the traditional clinical model, since metabolic acid-base disorders in particular are understood within a completely different pathophysiological framework; this results in a fresh and sometimes unexpectedly helpful perspective that highlights the functional relevance of seemingly forgotten components such as the chloride ion or albumin.