The possible reasons for the smell of urine are as follows: first, the presence of urinary tract infection, when the bacteria in the urine can decompose other substances such as protein in the urine, which can cause an increase in the volatility of ammonia substances, then there can be a heavy smell of urine, accompanied by frequent urination, urinary urgency, painful urination and other symptoms, accompanied by cloudy urine, need to carry out urine routine, urine culture examination to further confirm the diagnosis. Second, if the diet of meat or acidic diet increases, it can lead to an increase in the secretion of ammonia in the urine, resulting in a decrease in the pH of the urine and an increase in volatile substances in the urine, which can be manifested as a more tart smell of urine, generally without any sense of urination symptoms. Thirdly, when the urine is extremely concentrated, the smell of urine can appear, such as prolonged urine holding, dehydration, less water, insufficient water supplementation or urinary retention, and urine stays in the bladder for more than 4 hours, the smell of urine can appear more testy, and at the same time, it can be accompanied by yellowish urine, not accompanied by painful urination and other symptoms.