In the OVA of Miss Kobayashi's Dragon Maid, Kobayashi ate a chocolate love potion that almost affected her (didn't work completely because the chocolate had liquor in them). However, Kanna ate some of the chocolate, and she was fine.
I tried reading the manga for some answers, but all I know is that when Tohru saw her eating the chocolate, she said that she won't be affected.
Why is that?
While I don't believe that the specific cause to why Kanna was immune to the love potion were ever fully explained, let's consider in universe that she's eaten butterflies and whole crabs before (in her human form, no less).
One relatively reasonable theory is that Kanna simply has an indomitable digestive track and would not be subject to the kinds of after-effects of meals that would otherwise work on humans.
Its simple.
Just imagine, In reality...a child (havent hit puberty yet) use a medicine to increase libid0. Im sure in won't make any visible effect.
Thats why kanna is fine and not affected
