Abstract: The present invention provides methods for treating Pneumocystis carinii pneumonia and Giardia lamblia in a subject in need of such treatment. The methods comprises administering to the subject a compound of Formula I: ##STR1## wherein: X and Y are located in the para or meta positions and are selected from the group consisting of H, loweralkyl, loweralkoxy, and ##STR2## wherein: each R.sub.1 is independently selected from the group consisting of H, loweralkyl, alkoxyalkyl, hydroxyalkyl, aminoalkyl, alkylaminoalkyl, cycloalkyl, aryl, or alkylaryl or two R.sub.1 groups together represent C.sub.2 -C.sub.10 alkyl, hydroxyalkyl, or alkylene, or two R.sub.1 groups together represent ##STR3## wherein m is from 1-3 and R.sub.7 is H or --CONHCR.sub.8 NR.sub.9 R.sub.10.