Urine is sterile until it reaches the urethra where the epithelial cells lining the urethra are colonized by facultatively anaerobic Gram negative rods and cocci.[3] Subsequent to elimination from the body, urine can acquire strong odors due to bacterial action,[citation needed] and in particular the release of asphyxiating ammonia from the breakdown of urea. In medieval times clothes were stored in a garderobe (literally 'to guard ones robes') close to the toilet shaft because this ammonia would kill the fleas.[4] The term garderobe became a euphemism for toilet for that reason.
Some diseases alter the quantity and consistency of the urine, such as sugar as a consequence of diabetes. Beeturia, which affects some 10–14% of the population, results in the excretion of betanin after eating beets (such as beetroot) resulting urine with a pink/reddish color.[5] Beeturia can appear and disappear in individuals.[6]
