Dogs (Canis lupus familiaris) should if possible avoid hops (Humulus lupulus). For dogs ingesting hops can, and often do, overheat to an alarming, sometimes life-threatening degree. *see note. The physiological pathways involved are as yet poorly understood unknown. See: Toxicology Brief: Hops Make Dogs Hot, Veterinary Technician, August 2013 (Vol 34, No 8).
* Note:
Improbable has tried to find research regarding spontaneous combustion amongst canines, with very little, if any, success.
Photo credit: The picture, via Wikipedia, shows a healthy Whippet, a breed of Sighthound, which it seems are particularly susceptible.