Urolithiasis, urinary calculi, is one of the common diseases of the urinary system. Bladder stones and kidney stones were found successively in Egyptian mummies as early as 4,000 years BC. The disease is most common in 20-40 years old, with a male to female ratio of 4.5:1. There are certain regional and ethnic variations. Most of the kidney stones are mixed calcium oxalate and calcium phosphate stones and simple calcium oxalate stones. 80% to 95% of the kidney stones are calcium stones. The process of kidney stone formation is caused by certain factors that increase the concentration or decrease the solubility of crystalline material in the urine, resulting in supersaturation, precipitation of crystals and local growth and aggregation, and finally the formation of stones. The two most important factors in this process are the formation of supersaturation of urinary crystalline material and the decrease in the content of crystalline formation inhibitors in the urine. Factors affecting stone formation (a) Increased excretion of urinary crystalline material 1. high calcium urine 2. high oxalic acid urine 3. high uric acid urine 4. high cystine urine 5. xanthine urine (b) The effect of other components of urine on stone formation 1. urinary PH urinary ph changes have an important effect on the formation of kidney stones. ph decreases in favor of uric acid stones and cystine stones, while ph increases in favor of calcium phosphate stones (ph Ph decreases for the formation of uric acid stones and cystine stones, while ph increases for the formation of calcium phosphate stones (ph > 6.6) and magnesium ammonium phosphate stones (ph > 7.2). 2, urine volume is too small, the concentration of crystalline material in the urine increases, which is conducive to the formation of supersaturated state. About 10% of kidney stone patients in addition to daily urine volume less than 1L, without any abnormalities. 3.Magnesium ion Magnesium ion can inhibit the absorption of oxalic acid in the intestine as well as inhibit the formation of calcium oxalate and calcium phosphate crystals in the urine. 4, citric acid can significantly increase the solubility of calcium oxalate 5, low citrate urine citrate and calcium ions combined to reduce the saturation of calcium salts in the urine, inhibit the crystallization of calcium salts. The reduction of citrate in urine facilitates the formation of calcium-containing stones, especially calcium oxalate stones. Hypocitraturia is seen in any acidified state such as renal tubular acidosis, chronic diarrhea, post-gastrectomy, hypokalemia due to thiazide diuretics (intracellular acidosis), excessive intake of animal protein, and urinary tract infections (bacterial breakdown of citrate). (iii) Urinary tract infections Persistent or repeated urinary tract infections can cause infective stones. Bacteria containing urea-degrading enzymes such as Aspergillus, some Klebsiella, Enterobacter aerogenes, and Escherichia coli can break down urinary urea to produce ammonia, which increases urinary ph and contributes to the supersaturation of ammonium phosphate and carbonate apatite. In addition, the pus mass and necrotic tissue from the infection also contribute to the crystals gathering on its surface to form stones. (iv) Diet and drugs Drinking hard water; malnutrition, lack of VitA can cause urinary epithelium to shed and form stone cores; taking sulfonamides, etc. In addition, about 5% of patients with stones do not have any biochemical abnormalities, and the cause of starting stones is unclear. Types of stones Calcium phosphate stones, calcium oxalate stones, uric acid stones, cystine stones. Clinical manifestations The symptoms of urinary stones depend on the size and shape of the stone, its location, and the presence of complications such as infection and obstruction. (a) Asymptomatic. (ii) Pain. (C) Hematuria. (iv) Urinary blockage. (v) Symptoms of urinary tract infection.