Urinary tract infection is a broad term that refers to inflammatory lesions caused by pathogenic bacteria (non-tuberculous or other specific pathogens) invading the urinary tract, which is commonly referred to as urinary tract infection, the latter being subdivided into upper and lower urinary tract infection, with pyelonephritis belonging to upper urinary tract infection and cystitis (including acute hemorrhagic cystitis) and urethritis belonging to lower urinary tract infection. Clinical cases of lower urinary tract infection without evidence of pyelonephritis are often found to have been invaded by renal parenchyma by renal biopsy or autopsy, so clinically it is difficult to separate upper and lower urinary tract infections distinctly with simple, economical, and non-invasive tests, often diagnosing urinary tract infections. Nephritis and pyelonephritis are two different families and two different diseases of the kidney. Nephritis is usually short for glomerulonephritis (of course, in addition to interstitial nephritis, lupus nephritis, purpura nephritis, hepatitis-associated nephritis, etc.), which is an immunomimetic disease, not a direct bacterial invasion of the kidney, and antibiotic therapy is ineffective; pyelonephritis is an infectious disease, caused by direct pathogenic bacteria (bacteria, mycobacteria, viruses, etc.) invasion of the kidney, and antimicrobial and corresponding antipathogenic therapy Effective. Acute pyelonephritis can be cured, but it can recur, just like a cold, this time it is good, but there is no guarantee that it will not recur; chronic pyelonephritis can develop into uremia after several decades. There are three routes of infection: 1) upstream infection; 2) bloodstream infection; and 3) lymphatic tract infection. There is a condition that is indirectly related to catching a cold: respiratory tract infection occurs first after freezing, tonsillitis (or septicemia), bacteria enter the bloodstream, invade the kidneys, stay and multiply in the kidneys, and cause bloodstream infection pyelonephritis. There are a few people who lack knowledge of the disease and think it is a “sexually transmitted disease”, a disease that cannot be seen, and are even very disgusted and afraid. I told them: I’m afraid there are very few women who have never had a urinary tract infection in their lives, only the severity is different, and many have cured themselves without consulting a doctor; those who are not married can also get it, only the cause is different.