This is a bit out of date, as he's been released, but for the sake of completeness I'll post what I've found.
from an ESPN posted AP article:
Asked last week about getting Vanderjagt out of his rut,
Parcells said: "I don't have a Dr. Livingstone's frozen elixir. I
don't. I don't know what I can do. This guy is 36 years old and has
been kicking for a long time. He has his way of doing things.
Hopefully, things get a little bit better."
This led to some speculation as to what Dr. Livingstone's frozen elixir is/was.
First of all, I'm always wary of AP articles. They often misquote people.
e.g. Another AP article which obviously misquotes Parcells.
Parcells said. “There are things that happen out there that people aren’t cognitive of.”
Clearly he said (or meant) "cognizant" instead of cognitive. Even if he did misspeak, the writer could've fixed it with bracketed notation.
Anyway, so maybe he did says Livingstone's frozen elixir. What he was most likely referring to was Chartreuse Liquer (Elixir), which is not frozen:
History of the Chartreuse Liqueurs
And as this page points out:
Its reputation as a medicine was augmented even as late as the 19th century when it was widely used as a treatment in the cholera epidemic that swept Paris in 1832. It is even reputed that the explorer Livingstone took the drink into Africa as a solution to the many diseases rife in the jungles.
However, the Chartreuse trivia page reports:
Sir Henry Stanley
British explorer/journalist Sir Henry Stanley was known to bring Chartreuse Elixir on his expeditions into Africa while searching for Dr. Livingstone.
So, did Livingstone carry it or did Stanley? Or did both? I go with both, but the jury is still out.