SEEING BLOOD IN URINE IS A BAD SIGN

Body fluid are contained in their own department and,ideally,do not mix. For example,  blood is in the blood vessels and does not mix with saliva or urine.
Blood in brain fliud:  bleeding into the Brain fluid occurs commonly following a head injury or after a stroke. Of course, if it's due to stroke, it can kill and so needs urgent investigation with a CT brain scan and management as required.
Blood in saliva or cough: Blood should not appear in saliva or cough.  In cough especially,  it could signify an infection such as pneumonia or,  God forbid,  cancer.
Blood in vormit:  if u vomit fresh blood or even dark, foul smelling vomit, please endeavor to have someone look at you seriously. This could be mean you have a bleeding stomach ulcer.
Blood in urine: urine should be normal and dark.  Foul, tea coloured or frankly bloody urine demands review. Sometimes,  what appears to be blood in urine is actually red pigment from other sources such as food dyes, certain medication, or an excessive amount of beets. This can occur in some people who eat beetroots. The commonest cause of blood in urine is an infection and can be caused by the kidney or bladder which could be responsible.