How Is Urine Made?

Urine is made by the kidneys and stored in the bladder until you’re ready to go. Your kidneys act as a filter, removing waste products and excess water from the blood while keeping important substances like blood cells and larger protein molecules circulating in your body.

Most of the water filtered by the kidneys is reabsorbed back into your bloodstream. The amount of water reabsorbed depends on how hydrated you are. When you’re slightly dehydrated, your body retains more water and your urine becomes more concentrated – darker yellow in color. When you’ve had enough to drink, your kidneys allow more water to leave the body, making your urine paler and more diluted.

Why Is My Urine a Strange Colour?

As urine contains waste products filtered from the blood, its colour can be affected by certain foods, medications and medical conditions.

For example, about 1 in 10 people notice that their urine turns red after eating beetroot – a condition called beeturia. This is harmless and more common in people with anaemia.

Some medications such as senna, phenolphthalein (a laxative) or rifampicin (used to treat tuberculosis) can also discolor urine, turning it red, brown or orange.

However, unusual urine color – especially red, brown or smoky – can also indicate blood in the urine, known as haematuria.  This may be caused by:

• Urinary tract infections (UTIs): Cystitis, an infection in the bladder, often causes frequent urination, burning or stinging pain during urination, lower abdominal pain, and cloudy or pink-coloured urine with a strong odor.
• Kidney infections (pyelonephritis): This more serious infection may cause back pain, fever, chills, nauseas, vomiting and red or pink urine. Pyelonephritis requires antibiotics and plenty of fluids to prevent kidney damage.
• Other cases: Blood in the urine can also result from kidney or bladder stones, traumas or tumours, including bladder or kidney cancer.

Drinking plenty of fluids can flush out bacteria from the urinary system. Cranberry juice is thought to stop the bacteria sticking to the bladder wall and prevent an infection. However, if these symptoms do not go away, however, antibiotics may be needed to clear up the infection.

First published on embarrassingproblems.com
Reviewed and edited by Dr Diane K. Newman
Last updated: July 2025 by Dr Diane K. Newman