I'm not going to pretend I grasped everything Luci Zahray (The Poison Lady) had to say about alcohols at Magna cum Murder this past weekend, but I want to share the bits I did understand. Or misunderstand, as the case may prove.
Every year, college students die of alcohol poisoning. That's because any alcohol is toxic in large enough quantities, and a toxic dose varies according to many factors: concentration of alcohol, size of drinker, what's in the drinker's stomach, over what length of time the dose is taken. Booze is ethanol (anything ending in "ol" is an alcohol, I think....).
And, not only can you die from drinking to much ethanol (either quickly or over the course of many years), you can die from ethanol withdrawal (the DT's). Trap a habitual, always-a-little-drunk victim where he or she can't replenish the ethanol in his or her system, and you've got a sober corpse without a mark on it.
On the other hand, when medical folks talk about TOXIC alcohol, they usually mean isopropanol, methanol, and ethylene glycol, and ethanol is an ANTIDOTE to those.
Ethylene glycol is the ingredient in anti-freeze that makes it smell and taste sweetly fruity, and also that makes it toxic. Actually, it isn't toxic in itself, but it becomes toxic as it's digested. Mix some of that in Mr. Boddy's Sangria and he'll get happily looped, then he'll slip into a coma, maybe have seizures, and die.
A SERIOUS NOTE: Make sure any cough syrups/cold syrups you buy do not contain ethylene glycol. Sometimes some countries use a bit of it to sweeten the mixture because it's cheaper than sugar.
For more about alcohol poisoning and antidote, see:
Whiskey Cure After Anti-Freeze Error
Fantasies, mysteries, comedies, recipes