The main job of the kidneys is to remove waste from the blood. Kidneys are two bean-shaped organs found in the lower back, one on each side of the spine. They are part of the body’s filtering system.

Every day, your body creates waste from the food you eat and from your body’s own processes. This waste is carried in the blood. If it stays in the blood, it can be harmful. That’s where the kidneys come in.

The kidneys filter the blood. They remove:
- **Waste products**
- **Extra water**
- **Salts and minerals your body doesn’t need**

This waste becomes **urine**, which travels from the kidneys to the bladder and leaves the body when you go to the bathroom.

Kidneys also help in other ways, like:
- Balancing water and salt levels
- Controlling blood pressure (but this is not their main job)
- Producing hormones for making red blood cells

However, their **main and most important role** is removing waste. Without kidneys, harmful things would build up in the blood and make a person very sick. That’s why people with kidney failure need dialysis, a machine that does the kidney’s work.

In simple words, kidneys work like a water filter. They clean the blood and keep the body healthy by removing things the body doesn’t need.