Whether pyelonephritis is scary or not mainly depends on the condition and treatment effect. If the condition is mild and the treatment effect is good, it is usually not scary; if the condition is severe and the treatment effect is poor, serious complications such as infectious poisoning occur, or chronic pyelonephritis develops into chronic renal failure, the situation is more scary. Pyelonephritis belongs to upper urinary tract infection, most of the pyelonephritis is caused by bacterial infection, which can be divided into two stages: acute and chronic, most of the patients with mild as well as acute stage can be cured after active treatment, and if it evolves into chronic pyelonephritis, it can be treated to improve the symptom, and it’s not scary if the treatment effect is good. However, if acute pyelonephritis is not treated in time or the treatment effect is not good, complications such as pyelonephritis, perinephric abscess, infectious toxicity and so on may occur, or the condition of chronic pyelonephritis continues to progress, and it may develop into chronic renal failure, which is a more horrible situation. Patients with pyelonephritis are advised to go to regular hospitals in time and receive standardized treatment under the guidance of doctors.