Urine is the end metabolites produced by blood through glomerular filtration, renal tubular and collecting duct reabsorption and excretion, and is an important component of human body fluids. Fresh urine is mostly weakly acidic, with random urine pH 4.5-8.0 and morning urine pH about 6.5. Urine pH is affected by food, drugs and various diseases. Decrease in pH: It is common in eating meat (containing sulfur and phosphorus) and mixed food, etc., taking acidic drugs such as ammonium chloride and vitamin C, acidosis, hyperthermia, diabetes, gout, etc. Urine can also be acidic in patients with hypokalemic metabolic alkalosis. Increased pH: It is common to eat vegetables and fruits (containing potassium and sodium) to take alkaline drugs such as thiazide diuretics and sodium bicarbonate, alkalosis, cystitis and renal tubular acidosis, etc. In addition, urine left too long due to the release of ammonia from the decomposition of urea can make the urine alkaline. Drug intervention: Urine pH can be used as another indicator of drug administration. Acidifying urine with ammonium chloride can induce alkaline drugs to be excreted from urine, while alkalizing urine with sodium bicarbonate can induce acidic drugs to be excreted from urine. Therefore, urine pH is affected by food, medications, and a variety of diseases, and its testing can only be used to assess some disease states, not to confirm a diagnosis.