Hygiene. Because they had no running water, there was no such thing as flush toilets. Generally sophisticated plumbing facilities were an outhouse built over a cesspit. Those living more comfortably might have a chamber pot which they used in the evening and which would then be emptied into the cesspit in the morning. After defecating, people used hay, straw, grass, or some other vegetation to wipe themselves. Because of a relatively lack of privacy when grooming or attending to basic bodily needs, it appears that people had a higher threshold of embarrassment than modern people. These thresholds also applied to the use of bodily fluids. "Medieval people were not very squeamish about urine: not only was it an essential element in tanning leather and fulling cloth, but the medieval physician's analysis of a patient's urine was expected to take into account taste as well as appearance." (Singman, 50)

http://www.cas.sc.edu/hist/faculty/edwardsk/pubs/dailylife.html

This refers to Jeffrey L. Singman. Daily Life in Medieval Europe. Westport, CN: Greenwood Press, 1999. which I will have to take a look at. Does anyone have it?