It is not immediately made clear how Trolls differ from [[Muggles' Guide to Harry Potter/Magic/Giant/|Giants]], but from context we can assume that trolls are slightly smaller, have less brain, and are largely untrainable. From the fact that [[Muggles' Guide to Harry Potter/Characters/Harry_Potter|Harry]] and [[Muggles' Guide to Harry Potter/Characters/Ron_Weasley|Ron]] both commented on the smell when the troll approached them in ''Harry Potter and the Philosopher's Stone'', but that neither Harry nor [[Muggles' Guide to Harry Potter/Characters/Hermione_Granger|Hermione]] noted any smell when approaching [[Muggles' Guide to Harry Potter/Characters/Grawp|Grawp]] in [[Muggles' Guide to Harry Potter/Books/Order_of_the_Phoenix|Harry Potter and the Order of the Phoenix]], would also imply that Trolls are also much smellier than Giants.
