The LD50 in rats for caffeine is < 200mg/kg and this MSDS has a neat skull & crossbones under the words "toxic if swallowed": https://www.fishersci.com/shop/ms

The LD50 in rats for caffeine is < 200mg/kg and this MSDS has a neat skull & crossbones under the words "toxic if swallowed": https://www.fishersci.com/shop/msdsproxy?productName=O1728500 https://www.fishersci.com/shop/msdsproxy?productName=O172850... ...also for reference caffeine seems to be more than an order of magnitude more toxic than pure ethyl alcohol by weight.