Pyelonephritis, also known as an upper urinary tract infection, is a bacterial inflammation, with over 95% being caused by bacterial infections, among which 70% are caused by Escherichia coli. Therefore, as a bacterial infection-induced inflammation, antibiotic treatment is of course necessary. Clinically, third-generation cephalosporins or fluoroquinolone antibiotics are often chosen for bactericidal treatment. For acute pyelonephritis, it is generally recommended that medication be administered for 14 days, alongside measures such as increased water intake and frequent urination. In cases of chronic pyelonephritis, a low-dose, long-course antibacterial treatment, such as using nitrofurantoin, may also be employed, with continuous medication for two months. (Please consult a clinical doctor for specific medication use; do not self-medicate.)