The red cells in the urine may be caused by the following reasons: firstly, glomerulonephritis is the main cause and may be accompanied by frequent and urgent urination, which can be treated with oral medication under the guidance of a doctor. Secondly, urinary tract infection is likely to cause red blood cells in the urine, and usually drink less water and long time sedentary have a lot to do with it, usually there will be burning urine and stinging urine. Drinking more water and urinating more often can have the effect of flushing the urethra and can also effectively relieve the symptoms. Again, it may also be caused by kidney stones, kidney stones can be taken orally under the guidance of a doctor to remove stones particles. Finally, tumors and trauma may cause urinary occult blood, so further tests are needed to identify the cause.