  Let $X$ be a dendrite with set of endpoints $E(X)$ closed and let $f:~X \to
X$ be a continuous map with zero topological entropy. Let $P(f)$ be the set of
periodic points of $f$. We prove that if $L$ is an infinite $\omega$-limit set
of $f$ then $L\cap P(f)\subset E(X)^{\prime}$, where $E(X)^{\prime}$ is the set
of all accumulations points of $E(X)$. Furthermore, if $E(X)$ is countable and
$L$ is uncountable then $L\cap P(f)=\emptyset$. We also show that if
$E(X)^{\prime}$ is finite then any uncountable $\omega$-limit set of $f$ has a
decomposition and as a consequence if $f$ has a Li-Yorke pair $(x,y)$ with
$\omega\_f(x)$ or $\omega\_f(y)$ is uncountable then $f$ is Li-Yorke chaotic.

Dynamical Systems