I figured I might as well post a question I've been contemplating for a while.
I need a poison that will kill in a way that to the non-expert would look like a heart-attack or other natural cause, but that a specialist could identify fairly easily. Preferably a rather slow and painful death - it only needs to look natural afterwards, not necessarily while doing the dirty work.
The particular story is fantasy genre, so there will be no modern science to detect it.
This also gives me some leeway with the actual poison - it needn't be an real one, but I'd prefer to use effects similar to those of a poison or substance known to exist. ( The 'but it could work' factor. )
My first rounds of googling hinted at strychnine, but maybe there's something even more suitable? Strychnine sounds rather bitter, and a tasteless poison would be better.
Edit: If some med student or the like could help me describe classical signs of heart failure as cause of death, it would be much appreciated. It's much easier to compare the results of poisoning to the real deal if you know what the real deal is.
So far my google-fu only finds warning symptoms of heart attack you can feel yourself while alive, nothing on how it's concluded as cause of death in someone found dead.
Edit 2: Most poisons suggested so far have symptoms that include diarrhea and / or vomiting. I'm more after something that's painful, but not overly messy. It should kill within half an hour, one hour tops. Cramps, panic, severe agony etc are all fine, more messy effects should preferably be avoided.
Lots of pain, but a decently dignified corpse sounds about right.
Also, some medical info about the similarities / differences between a natural death by heart failure and death caused by different poisons would be gold. What would an expert look for that could rule out natural death and hint at more sinister deeds?