Before hydronephrosis is adequately treated and before the obstruction in the urinary system is resolved, in areas such as the renal pelvis and calyces where there is fluid accumulation, it is advised that patients should not drink tea and should try to reduce their fluid intake. This is because the fluids cannot be excreted through the kidneys, and drinking large amounts of water at this time could worsen the obstruction and may also lead to edema. Therefore, patients are advised not to drink tea until the hydronephrosis is resolved. Once the causes of urinary tract obstruction, such as urinary system stones or tumors, have been removed, patients can increase their water intake, but it is still recommended not to drink tea because tea contains considerable amounts of oxalate, which can lead to the recurrence of kidney stones.