I've searched: "2 part poison" "two part poison" "compound poison" - all I'm getting is either references to poisoning stories with "2 parts" or "compounds that are poisonous" - I know I've seen the concept in murder mysteries - anyone have any idea how to hunt for this?
EDIT Binary poison has been suggested and is giving me some good results ;>.
The real need here is for the two parts of the binary poison to be ingested at completely separate and unrelated times. The poisoner needs to be able to be completely in the clear - and if he gives one part now and someone else gives another part later (or regularly ingested drugs do the same thing), he can walk blameless.
EDIT 2 yum - I think I found a way to pull this off - tho it requires some sneakiness (and some ongoing meds :>) - not quite what I was thinking in terms of, but might work... :> Thanks everyone!