Dialysis is the artificial process of getting rid of waste products and unwanted water from the blood. This process is naturally done by our kidneys. When the kidneys are damaged or have failed they cannot carry out their functions properly, therefore the need for dialysis arises.

In other words, dialysis is the artificial replacement for lost kidney function (renal replacement therapy). Dialysis may be used for people who have become ill and have acute kidney failure (temporary loss of kidney function), or have chronic kidney failure with permanently lost kidney function.

When we are healthy, our kidneys regulate our body levels of water and minerals, and remove waste. The kidneys also produce erythropoietin and 1,25-dihydroxycholecalciferol (calcitriol) as part of the endocrine system. Dialysis does not correct the endocrine functions of failed kidneys - it only replaces some kidney functions, such as waste removal and fluid removal.

Dialysis performs the two main functions of the kidneys:

Approximately 200 liters of blood are filtered by a healthy person's kidneys each day. We could not live if waste products were not removed from our kidneys. People whose kidneys either do not work properly or not at all experience a buildup of waste in their blood. Without dialysis the amount of waste products in the blood would increase and eventually reach levels that would cause coma and death.

Although dialysis helps patients whose kidneys have failed, it is not as efficient as a normal kidney. Consequently, patients on dialysis need to be careful about what and how much they drink and eat. They will also need medications.

A significant number of patients on dialysis can work and lead normal lives. It is possible to go away on vacation as long as dialysis treatment is possible at their destination.

Women on dialysis will probably not be able to get pregnant. There will be a higher level of waste products in the body compared to a woman with normal kidneys - this interferes with fertility. Women who do become pregnant while on dialysis will probably need increased dialysis during the pregnancy. If a woman has a successful kidney transplant her fertility should return to normal. Dialysis has some effect on male fertility, but much less than on female fertility.