Body fluids are having balanced quantity of acids and bases and this quantity is maintained by intricate mechanism. The maintenance of this balance quantity is necessary for biochemical reaction talking places in body, because biochemical reaction are very sensitive to even small change of acids and bases.

Example: Low pH value in stomach is requiring for functioning of enzyme pepsin which is useful for digestion of food.

The pH values of certain body fluids are given in table.

Body is having its own buffer system which prevents drastic change in the pH value of blood. It also helps to convert strong acids and bases into weak acids or bases. Lungs and kidney are the main organ which helps to maintain buffer system in the body.

In case of low respiration, the accumulated carbon dioxide combines with water and forms carbonic acid which releases hydrogen ions and causes acidosis.

CO₂ + H₂O →  H₂CO₃  →   H⁺ + HCO₃^-

In over breathing, excessive excretion of carbon dioxide occurs and causes alkalosis.

Kidney has ability to generate ammonia which neutralizes acid products of protein metabolism and excrete in urine

Conditions where metabolic acidosis occurs:

1. Failure to excrete metabolic acids
2. Formation of excessive quantities of metabolic acids like carbonic acids
3. Loss of base from body fluids
4. Absorption of excess metabolic acids
5. Diabetes mellitus
6. Diarrhoea
7. Excess vomiting
8. Uremia

Conditions where metabolic alkalosis occurs:

1. Administration of diuretics
2. Excessive ingestion of alkaline drugs
3. Loss of chloride ions
4. Endocrine disorder

Examples of drugs used in acid-base imbalance:

1.    Potassium citrate

2.    Potassium acetate

3.    Sodium bicarbonate

4.    Sodium acetate

5.    Sodium citrate

6.    Ammonium chloride