Lithium is the more toxic of the alkaline metals. However, its effects can be neglected because the element does not have any important risk to human health. The excessive ingestion of lithium compounds should be avoided because they can cause nervous disturbs and dizziness. The ingestion of lithium chloride is recommended, in certain diets to substitute the traditional sodium chloride; even in these cases, it can originate dizziness, visual disturbances, and shivering or mental confusion. These symptoms dissuade the ingestion of these compounds, in spite of the fact that it is not cumulative. However, lithium compounds, in appropriate doses, are used in the treatment of maniac-depressive diseases.

Lithium is not an indispensable element in the plant growth and there is no indication that it could play an important role in animal biology. The mentioned adverse effects are probably due to the disturbances caused by the lithium in sodium-potassium-calcium balance of the living cells.