The purpose of this study was to evaluate the desired and undesired effects of relapse-preventive lithium treatment given routinely to manic-melancholic patients who had accepted the necessity of a strict tablet regime. The evaluation was based upon case record data and various rating scales, and 76 patients took part in the investigation. Our results showed that in 24 % of the patients treatment was discontinued. This was due to side effects in 16 % and to insufficient effect in 8% of the cases. The suicide risk was not eliminated, and 29 % of the patients were receiving additional antidepressive or antimanic treatment at the test day. On the other hand, 78 % of the patients rated the relapse-preventive lithium effect as moderate to excellent. Indirect evidence was obtained in support o a stabilizing effect of lithium on the emotional control in bipolar patients. The most frquent complaints during lithium treatment were tremor and increased thirst.