Frequent urination after lunch is considered to be related to urethritis, cystitis, pyelonephritis and other diseases, you can go to the hospital in time for examination to clarify the cause of the disease, and then carry out the corresponding treatment under the guidance of the doctor. 1. Urethritis: generally due to the urethra in the inflammatory stimulation, so that the urethral mucosa is damaged, after eating lunch food will be gradually digested in the stomach and intestines, excess water will gradually enter the bladder, pressure urethral inflammation, which in turn causes the phenomenon of frequent urination after lunch, urethritis may appear urinary urgency, painful urination and other symptoms. 2. Cystitis: usually due to the mucous membrane in the bladder is damaged under the stimulation of inflammatory mediators, the water after meals gradually enters the bladder, stimulating the damaged mucous membrane, which in turn causes the phenomenon of frequent urination after lunch, and there will be symptoms such as urinary urgency, urinary pain and so on. 3. Pyelonephritis: it may be due to pyelonephritis belongs to the upper urinary tract infection, the kidneys in the inflammation, so that its metabolic function is abnormal, and then the phenomenon of frequent urination after lunch, pyelonephritis usually appear chills, nausea and other symptoms. If the phenomenon of frequent urination after lunch occurs, you should go to the hospital in time to avoid adverse consequences.