This paper describes the use of lithium carbonate in the treatment of ten patients with manic-depressive disorders, manic type. In keeping with previous reports, we have found this to be an extremely effective method of controlling manic excitement. The patients maintained on lithium carbonate have continued to do very well and while the follow-up period has not been long, none has had any recurrence of manic or depressive symptoms. At the dosage level used, side effects have been rare and transient. The practical aspects of a treatment that is effective, safe, and inexpensive are obvious but lithium may also be an interesting tool that can be used to better understand the nature of manic depressive illness.Abstract Teaser