Lithium is a mood stabilizer frequently used in psychiatry to treat bipolar disorder. Because lithium has a narrow therapeutic index, it requires frequent monitoring for its toxicity. Lithium toxicity requires monitoring of serum lithium and clinical assessment by clinicians. Sialorrhea, also known as excessive drooling, hypersalivation, or ptyalism, is common among psychiatric patients. Sialorrhea, an infrequent and embarrassing side effect of lithium, has been reported at varying serum levels, either at subtherapeutic or in the normal range. Here, we present the case of a patient with sialorrhea associated with oral lithium therapy at the subtherapeutic serum level.