1. 1. Fever and leukocytosis are occasionally observed in patients with psychiatric disorders. A thorough medical evaluation does not always reveal the origin of these abnormalities.2. 2. We report the case histories of three patients with bipolar affective disorder and an abnormal DST who had fever and leukocytosis during the acute phase of their illness. No organic etiology could be found.3. 3. All three patients responded to ECT with resolution of the depression, the fever, and the leukocytosis, and normalization of the DST.4. 4. We propose that fever and leukocytosis may be rare physical manifestations of bipolar affective disorder, particularly in patients with abnormal DST.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27598/1/0000642.pd