Pee (urine) is filtered from your blood by your kidneys, and does not come directly from your digestive tract (the system that turns food waste into poop) as you might have assumed.
Your kidneys are clever filters. Blood flows through them constantly, where they remove excess water, salts and waste chemicals. The result is urine, which is mostly water.
This gets stored in your bladder, where it waits to be expelled. Sometimes, disease means your kidneys can no longer filter things properly.
For example, diabetes causes excess blood sugar, which then gets filtered into your urine and can be used to help diagnose the condition.
Essentially, pee is your body’s way of maintaining balance, removing what it doesn’t need and giving us a tiny peek into how well our internal systems might be functioning.
This article is an answer to the question (asked by Hazel Owens, Canterbury) 'What is pee, actually?'
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