Such a poisonous addition is only topped in bizarreness by an additive reported by an English friar, Thomas Gage, traveling in 17th century Guatemala. The Cakchiquel people, he wrote, added a live poisonous toad to their fermenting vats which they then closed and left to ferment for several weeks. The Englishman wrote, “This drink they call Chicha, which stinketh most filthily, and certainly is the cause of many Indians deaths, especially where they use the toads poyson with it.” It is one thing to put a snake in a bottle of strong spirits. It is entirely another to throw a live animal into a non-alcoholic drink and expect the human stomach to drink of it without dying of botulism.
Poison in alcohol, on purpose! Any brewer today would advise against adding poison to a fermenting vat of beer, but such things were sometimes practiced. Even the agave root that was added to all pulque fermentations may have had some chemicals that could cause heart attacks in stronger concentrations. So why would native Mexicans add these poisons to their booze?
Bruman presents the most likely answer to this question. After surveying all of the whacky and trippy plants that ancient Mexican people added to their alcohol, he notices that some have a common trait; they are all cardiac poisons. He writes:
Although definite information is lacking, it is dangerous to generalize, but what evidence there is leads one to suspect that heart poisons are the main physiologically active substances introduced into fermenting mixture through the addition of pulque roots and related products. According to Fieser, these heart poisons, like digitalis extract, act as excitants in small quantities and raise the pulse rate. Artificially heightened stimulation in ritual drunkenness, leading to extreme exhaustion when the frenzy is over, must intensify the ceremonial significance of the act.
While the hallucinogens are easy to explain (the drinkers just wanted to trip), these cardiac poisons are a bit harder. It is necessary to consider how and why these special infusions were consumed to understand why a human would want to drink something that would literally make her heart flutter on and off. These drinks were ritualistic. Alcoholic intoxication, and even the rush of trace amounts of cardiac poisons, enhanced religious activity and helped worshippers feel closer to their gods. The plants were additives to the alcohols, but the resulting admixtures were also additives, only this time to religion itself!