The vast majority of urinary stones are currently treated by minimally invasive modalities, including: ESWL, PCNL, ureteroscopy, etc. Despite being relatively less invasive, they have some potential risks due to the need for anesthesia. Therefore, conservative treatment can be considered for small urinary stones. Effective, safe, non-invasive, and suitable for outpatients is undoubtedly the ideal choice for patients with symptomatic upper urinary tract stones who urgently need to remove stones, and such a drug expulsion therapy (Medical expulsion therapy) has become a hot spot for a large amount of basic and clinical research in the last decade. I. Factors affecting stone removal There are two main types of factors affecting natural stone removal: pathological factors: including urinary tract infection, edema and spasm; lithotripsy factors: including stone size, shape and location. The most important factors are stone location and size. Studies have shown that the rate of natural stone removal without medical intervention is about 29-98% for proximal ureteral stones less than 5 mm and about 71-98% for distal ureteral stones. In contrast, the natural stone evacuation rates for ureteral stones of 4-6 mm and greater than 6 mm were 59% and 21%, respectively. As a conservative treatment – the effect of natural stone removal is unpredictable, pharmacological stone removal therapy becomes a powerful complement to natural stone removal treatment. Based on the hypothesis that ureteral edema and spasm affect stone expulsion, the main drugs used for pharmacological stone removal therapy are: α1-blockers, NSAIDs/prostaglandin synthase inhibitors, etc. Studies have shown that α and β adrenoceptors and cholinergic receptors exist in ureteral smooth muscle, the most important of which is α1 receptor, and its density is significantly higher than that of β and cholinergic receptors [6], compared with the highest density of a1 receptor expression in the distal ureter. a1A receptor > a1B receptor. Among the known subtypes, α1 D receptors play the strongest role in distal ureteral spasm and contraction of the detrusor muscle, especially in the wall segment ureter, and thus play an important role in the physiology of the lower segment ureter. α1 receptor blockers can diastole ureteral smooth muscle and attenuate the frequency and amplitude of peristalsis, which can reduce the pressure in the wall segment ureter, enhance the urinary transmission capacity and urinary flow pulse, and correspondingly increase the ureteral pressure over the ureteral calculus. The α1 receptor blocker also acts on C-type fast-response fibers in the spinal cord and sympathetic postganglionic neurons, cutting off pain transmission to the central nervous system and reducing renal colic during stone evacuation. a1A receptors are mainly found in the proximal segment The a1A receptors are mainly found in the proximal urethra, prostatic urethra and bladder neck, and the a1D receptors are mainly found in the distal ureter, urethral smooth muscle and bladder forceps; a receptor blockers act on the prostate and bladder neck and are therefore now preferred for the treatment of lower urinary tract symptoms. Tamsulosin, which selectively acts on a1A and a1D, is currently the most commonly used drug for the treatment of BPH and prostatitis. In 2002, Cervenakov et al. conducted the first randomized double-blind trial of tamsulosin in 104 cases of distal ureteral stones and showed that tamsulosin was superior to the control group in terms of stone expulsion rate and duration of stone expulsion and control of recurrent colic. 2004 Porpiglia F et al. compared 86 distal ureteral stones less than 1 cm in size in three groups randomized to tamsulosin, nifedipine and a blank control and found that tamsulosin and nifedipine were both safe and effective in increasing the rate of stone evacuation and reducing the amount of pain medication, but the reduction in time to stone evacuation was more pronounced in the tamsulosin group. 2007 Sakip et al. compared tamsulosin and sernitin in In 2007, Sakip et al. compared the efficacy of tamsulosin and sernitin in stone removal from distal ureteral stones and found that tamsulosin promoted stone removal and sernitin had no stone removal efficacy. In 2005, Sefa used tamsulosin for the first time in the treatment of 67 patients with lower ureteral stones formed after ESWL of renal stones and found that the addition of tamsulosin to conventional conservative treatment was beneficial in reducing the number and extent of renal colic after ESWL. 2005, Gravina et al. conducted a randomized controlled prospective study of 130 patients with renal stones (4-20 mm) Patients undergoing ESWL were randomized into two groups: the experimental group was treated with standard drug therapy plus tamsulosin 0.4 mg once daily for a maximum of 12 weeks, and the control group was treated with standard drug therapy alone. The results showed that the 3-month stone free rate was 78.5% in the experimental group and 60% in the control group, and the success rate was higher in the experimental group especially for stones >1 cm. Drug-assisted lithotripsy after ESWL promoted ureteral stone expulsion and increased the stone free rate at 1 month and 2 months, and few of them required retreatment. This leads to increased pressure in the collecting system and stimulates prostaglandin secretion. Prostaglandins increase renal blood flow by dilating the small arteries into the bulb, which in turn causes increased pressure in the pelvis and ureter, exacerbating inflammation and edema, while the increased pressure can lead to renal colic, and also increases nociceptive receptors by increasing It can also further aggravate nociception by increasing sensitivity to chemical and mechanical stimuli, while experimental evidence shows that NSAIDs can inhibit prostaglandin synthesis, reduce inflammation by reducing vasodilation, and decrease glomerular rate filtration and intrarenal pressure. It was also demonstrated that cyclooxygenase 2 inhibitors can inhibit the release of prostaglandins and ureteral constriction. This may facilitate the discharge of stones. Although neither dichlorfenac sodium nor celecoxib significantly improved stone expulsion rates in a randomized double-blind controlled trial of stone treatment, they were able to significantly prevent and treat renal colic, while reducing hospital admissions. Therefore, NSAIDs are still commonly used in the treatment of stones. In conclusion, the choice of pharmacologic stone removal therapy for appropriate patients can be more effective in improving stone removal rates and reducing stone removal time, complications, medical costs, and hospitalization rates.