Lithium is one of the most incredible elements in the world. It is unique in many aspects. Despite its wide usage in manufacturing, it has been a proven, effective medication in psychiatry for decades. Its mood-stabilizing effects have led to its inclusion in national and international guidelines as a gold-standard in the treatment of both bipolar and unipolar affective disorder. Suicidality is one of the most challenging syndromes in mental illness. Its prevention and treatment options for healthcare providers are extremely important. Lithium’s anti-suicidal effects have been investigated in many international studies since the early 1990s. This effect was demonstrated by applying various designs, settings, and taking different statistical approaches including retrospective data analyses of suicides, suicide attempts, or suicidal behavior but also mortality data. Interestingly, this anti-suicidal effect has also been revealed in other research directions, i.e., the correlation between the lithium level in tap water and suicide rates. The following chapter provides a review of studies examining lithium’s anti-suicidal effects, discusses clinical implications, and offers a practical guide.