Urinary frequency is described by the National Institutes of Health website, Medline Plus, as a feeling that one needs to empty the bladder more frequently than usual; the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) further defines it as needing to urinate more than 8 times during the day. Caffeine can cause urinary frequency because it irritates the bladder, resulting in spasms of the bladder wall that are perceived by the person as an urge to urinate. Alcohol, via its effect of inhibiting water conservation, can also result in frequent urges to urinate. Urinary frequency can contribute to the other dehydrating effects of caffeine- and alcohol-containing drinks; a simple way to prevent the related, dehydrating side effects of caffeine or alcohol is to use them in moderation. While a cup of coffee daily, or a glass of wine with dinner, is not likely to result in dehydration, drinking excessively can lead to the unpleasant and potentially harmful symptoms of excess fluid loss.