I have noticed when I launch any grenade against someone who is affected by fear poison they do not take the damage. They flee after the broken glass and evade the big damage. I thought that was the case after I have attacked numerous people and re-engaged after throwing a couple grenades and they weren't any more damaged than before. Here is a log from Wojif showing exactly what I'm talking about. Oh, and sometimes I get the "your poison doesn't take hold" echo and sometimes I don't.

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Hentogi steps out of the shadows.
Hentogi launches a grenade-like vial filled with green liquid at you!
Hentogi's broken glass scratches you.
The Chamber of the Council of Four


Aereglen is here.
(Ghost) Xapoco is here.
Ronar has arrived.
Draqudaf has arrived.
Mlyarir has arrived.
You flee from combat!
You resist the affects of Hentogi's poisonous grenade.
You yell 'Help! Hentogi threw a grenade at me!'
Hentogi has some small but disgusting cuts.
<76-89%>

n/t