In physiology, acidosis is any condition tending to elevate the hydrogen ion concentration of arterial plasma, making the blood more acidic. Generally, acidosis is said to occur when pH falls below 7.35. Its counterpart (alkalosis) occurs at a pH over 7.45. Arterial blood gas analysis and other tests are required to seperate the main causes.

Types:

• Respiratory acidosis is acidosis due to problems in the lung that decrease oxygen intake in the blood and removal of carbon dioxide.
• Metabolic acidosis is acidosis due to primary disturbances in the removal of acid from the body (e.g. acidic poisons, iron etc.) or decreased production of bicarbonate.

Various degrees of compensation may occur, depending on the nature of the acidosis and integrity of the compensatory mechanisms.

Treatment depends almost entirely on the underlying cause.