Inquiring patients with urothelial tumors about their illness, we often encounter descriptions of such situations: finding red urine during daytime urination, or finding blood on underwear when urinating or defecating without any discomfort, or finding red urine at the bottom when emptying the toilet in the morning, which occurs only once, or only 2 to 3 times in a row, and often disappears before we can think whether it is a symptom of the disease, giving people the impression of “cure”. This gives the illusion of “cure”. The next time hematuria occurs, it is alarming, and at that time there is an interval of several months or even years. This kind of intermittent painless hematuria is the clinical characteristic of urinary tract tumors (including kidney cancer, renal pelvis tumor, ureteral tumor and bladder tumor, etc.). For example, in bladder tumors, hematuria as the first symptom can be as high as 80%. There are also a few patients who present with painful hematuria. For example, 5% to 10% of patients with bladder tumors show symptoms of bladder irritation, i.e. urinary frequency and urgency and painful urination, similar to “lower urinary tract infection”, but after careful analysis of their routine urinalysis results, microscopic hematuria is often the main symptom, not signs of infection. Another example is that patients with renal pelvic ureteral tumor may show dull pain in the lumbar region or renal colic with hematuria, similar to “kidney stone”, except that the colic is not caused by stones, but by blood clots or detached tumor tissue. Therefore, when hematuria occurs, regardless of the presence or absence of pain and the amount of bleeding (in rare cases, it is only microscopic hematuria), you should promptly go to the hospital and have a urinary system examination. Of course, not all painless hematuria is caused by tumors. In a few cases, kidney stones, renal tuberculosis, hydronephrosis, polycystic kidney, prostatic hyperplasia, etc. can also cause painless hematuria. All these distinctions can be determined only in the hospital. Also, there is no need to be alarmed at the sight of red urine, as some of them are not hematuria. This is easy to identify in the hospital. Non-hematuric red urine is seen in the following three cases: 1, food or drug-based red urine: there is contact or taking food or drugs such as aminopyrine, santoprene, rifampin, rhubarb, candy dyes, phenol red, beet, purple radish, etc.; the urine is clear and not turbid, and there is no red precipitation after resting; the urine is negative for occult blood; the urine specimen retained is free of red blood cells by microscopic examination. 2, uric acid salt urine: urine is clear and then cloudy; red urine disappears after oral administration of baking soda; the retained urine specimen is free of red blood cells by microscopy. 3, hemoglobinuria, myoglobinuria, porphyriuria: urine is also clear and not turbid, no red precipitation after standing; urine occult blood of hemoglobinuria and myoglobinuria is positive but no red blood cells under microscope; urine occult blood of porphyriuria is negative, no red blood cells under microscope; combined with medical history such as hemolysis, severe burns, crush syndrome, hematoporphyria, lead poisoning, etc., can be distinguished.