One only gets rebound in the nose, but I'll probalby screw it up trying to
explain why. (Let me run downstairs real quick and ask the live-in doctor.)
(OK, I'm back...) It has to do with the differences in the mucosa. The one of
the nose is more mucous producing while that under the tongue is not. When a
chemical is sprayed in the nose, it acts as an irritant which stimulates
mucous production. Not so sublingually.

Both areas have a good blood supply, which is needed to get the syntocinon
into circulation--so why not avoid rebound if it is someone using the spray
several times a day. (And not everyone does.) Oh yeah--my husband said it
could be sprayed into any body opening having a good blood supply--I won't
mention the example he cited.

Karen