What does it mean when a guy sees red in his pee rather than yellow? – or white or whatever the colour of men pee is. Sometimes it might be blood, somethings it might be some foods; foods like berries can change your pee color. The only way to know whether it’s blood or food (since you can’t taste it) is to go to a doctor and run tests. If you sight blood in your urine it’s actually serious, so be very afraid. The medical term is gross hematuria and the color of the blood may range from slight pink to brown to thick dark clots. So don’t just relax till it looks dark red. In a study, 47% of people who had gross hematuria were diagnosed with a kidney or urinary health problem and 41% out of the 47 had bladder cancer.