  We study a new class of quintessence models, in which the scalar field
possesses a O(\textit{N}) internal symmetry. We give a critical condition of
instability for the potential against Q ball formation. We find that the most
widely used potentials of quintessence don't satisfy the above condition, and
therefore the O(\textit{N}) quintessence with these potential will not lead to
the Q ball formation. It is worth noting that O(\textit{N}) quintessence with
cosine-type potential is especially interesting in that the angular
contribution is not negligible.
