The urethra is the final pathway of the urinary tract system; it is the tube connected to the bladder, from which urine flows. It is important to keep the entire urinary tract clean and clear because many infections, such as prostatitis, pyelonephritis and cystitis, are caused by bacteria. However, the urinary tract, under normal circumstances, is sterile. It is only when bacteria travels past the urethra and up through the kidneys that infections occur. Thus, clearing and cleansing the urethra is a good preventive measure.
Drink water. Under ordinary conditions, simply urinating is the body's natural way of cleansing and clearing particles and bacteria from the urinary tract and urethra. Make sure you're consuming at least 1,892ml. of water each day, and drink an extra 236ml. before and after exercising, after urinating, after drinking something caffeinated and before going to sleep.
Drink 2 glasses (473ml. each) of all-natural cranberry juice daily. It has been proved that cranberry juice prevents bacteria from latching onto cells in the urinary tract and creating an infection. This juice is superior because it doesn't disrupt the natural bacteria in the tract. Thus, even if you are not experiencing symptoms and are not susceptible to bladder or kidney infections, cranberry juice is a good substance to flush your system with, thus cleansing and clearing your urethra.
Take D-Mannose capsules. D-Mannose is a wonderfully simple substance: it's a simple sugar, very similar to glucose, and your body metablolizes very small amounts of it. Larger amounts, however, are transported into the urine and are excreted from the body. D-Mannose adheres itself to bacteria such as E. coli and prevents it from sticking to cells inside the urinary tract. This bacteria is then urinated out through the urethra, washing it and clearing this tube.