The following material was gathered from a thread on the ATHG Listserv in early 2004; it should not be used without verification:
Patron saints for alcoholism/reform of alcoholics include John of God, Martin of Tours, Matthias the Apostle, Monica (mother of St. Augustine of Hippo), and Urban of Langres. More recently, Father Matthew Talbot (ca. 1850 to ca. 1925) has been boosted as a potential saint. Talbot issued some temperance medals (condemned by contemporaneous Protestants as "supersitious tokens). He was associated with the Baltimore Diocese.
There was also a well-known Father Matthew who did temperance work in Ireland and elsewhere in the early 1800s, who also has been boosted for saint-hood.