Urine pull out a lot of red sand particles, may be urethritis, urinary stones, urinary tract tumors and other diseases caused. 1. Urethritis: usually pathogenic infection caused by inflammatory lesions of the urethra, inflammatory media stimulation of the urethral mucosa, it will lead to mucosal tissue breakage, bleeding. When the patient urinates, the sludge in the urethra will be discharged, and the symptom of red sand grains will appear. 2. Urinary stones: generally related to age factors, microbial infections, dietary factors and so on. When the patient urinates, the stone may be discharged with it. If the stone damages the urethra, a lot of red sand grains may appear. 3. Urological tumor: it is generally due to the urinary tumor that produces certain stimulation to the urethra, which may cause the phenomenon of pulling out a lot of red grains of sand in urine. If the patient has red grains of sand in urine, he should go to the hospital for diagnosis in time, find out the specific cause of the disease, and then choose the appropriate method of treatment under the guidance of the doctor.