The yellow stuff is a post-op infusion....I think they may use anti-nausea drugs in the anesthesia mix...but it may well have been something like Versed which is a tranquilizer....it all depends on what type of surgery they are doing...but I wouldn't worry too much. They won't let you leave the hospital/surgery center until you feel okay for the ride. Your fiancee probably won't need a bucket...but if it makes him feel useful...then let him bring it.