Thanks to the About.com people for a head's up on this one:
http://news.bbc.co.uk/2/hi/uk_news/scotland/4196350.stmAccording to the BBC, Brian Moffat at the Soutra Aisle archaeological dig, claims that the monks used bitter vetch as an appetite suppressant, and "there was also evidence that the monks treated cryptosporidium food poisoning with blaeberries, could induce women in difficult childbirth and used hemlock as an anaesthetic in more difficult operations."
Here's another link on the site:
http://www.undiscoveredscotland.co.uk/pathhead/soutraaisle/Apparently it was a hospital, which suggests that there may be some basis in fact. The archaeologist is employed by the local county council, from the looks of it, and I couldn't find any publications by him...