It is a mystery how this guy died. The symptoms sound like an allergic reaction to me. He drank ayahuasca and apparently at the same time put frog toxins on an open wound.
The article says “frog” toxins and not toad. I wonder if the journalist got that wrong because the active ingredient in ayahuasca is DMT, and DMT also happens to be present in the Bufo Alvarious toad (not frog).
Would be nice to know if it really was toxins from a frog or from the Bufo Alvarious toad. The DMT toxins secreted from the toad are enough to kill a small animal like a dog (this is the defensive purpose of the toxins) but not enough to kill a human AFAIK. Though I have no idea if it can threaten a human to smear a large amount of it on a wound which I suppose would be comparable to injecting it.
Why would he have a cut on his oesophagus? Since ayahuasca is made using tree bark (which contains the DMT) I wonder if a splinter from the bark would do that.