Enough To Choke A Horse Meaning

(idiomatic, informal) An excessive quantity.

Example:   You didn't have to buy enough wrapping paper to choke a horse, just because it was on sale.
1999, Tom Waits, "What's He Building?" from Mule Variations:
  There's poison underneath the sink, of course.
  There's also enough formaldehyde to choke a horse.