Well, I am very glad I asked that question about cabbage leaves and how to use
them, for two reasons.   First of all because I now know what to do when I get
that vegetable back from the greengrocer's and into the mom's house --- thanks
to the many who emailed me with helpful (and sometimes funny) descriptions, or
posted them to the list.

But second, because a couple of interesting questions have now been raised
about how the cabbage works.    A number of lactnetters suggested to me that
cabbage -- preferably straight from the refridgerator -- was basically just a
convenient, inexpensive way of putting cold compresses on the breast -- not an
herbal or otherwise pharmacological thing; just cheaper and easier to stick in
a bra than those bags of frozen peas.   In this version I wonder why people
would use it for swellings on body parts that are not, shall we say, cabbage-
leaf shaped?  especially if the cabbage has not been particularly kept cold?
Or maybe those who hold with this theory are not putting cabbage on their
sprained ankles at all?

Some others, though, had one of two other theories.   As Carla D'Anna
helpfully pointed out, if the cabbage actually has an "active ingredient" it
could be either one that reduces edema -- in which case it shouldn't reduce
milk supply, but could indeed be used on sprained ankles -- or one that
diminishes milk production -- in which case we should indeed take it off the
breast after a little while, but putting it on sprained ankles would be pretty
useless.

I also checked Jack Newman's helpful handout #24 on treatment of problems, on
Cindy's homepage, and it give the same method as others have given me.   He
writes that cabbage "seems to work more quickly than ice" and that it should
be stopped as soon as engorgement diminishes, both of which suggest that its
related to milk rather than just garden variety edema, but he doesn't address
the theory of it in that handout.

So, I am curious to hear whether anyone out there actually knows WHY cabbage
works, and how it works?    Is there any research out there, or are we all
working with the plural of anecdote?

Again, many thanks to all for the fascinating answers so far.   My mother
always told me that if you don't ask what seem to be dopey questions you won't
learn, and I find she is proved right again.

Elisheva Urbas,
once more at the feet of the wise in New York City