Small traces of cyanide can be found in apple seeds. But don't worry: The seeds do not contain enough cyanide to hurt you. You'd need to eat piles and piles of apple seeds at once to ingest enough cyanide to cause any harm. And by then you'd have a bigger problem what with those apple trees growing inside of you.
And I know that's a fact, Jack, 'cause my Daddy wouldn't ever make up somethin' like that!