The differential diagnosis of common diseases is as follows: 1. urinary tract stones: those with urinary frequency, urinary urgency and painful urination, i.e. bladder irritation, need to be differentiated from bladder stones; 2. urinary system tuberculosis: those with recurrent urinary frequency as a symptom need to be differentiated from urinary system tuberculosis; 3. endocrine system diseases: those with simple urinary frequency and no painful urination should be differentiated from those caused by endocrine diseases such as diabetes; 4. prostatic hyperplasia: elderly men with frequent urination should be differentiated from prostatic hyperplasia.