diff --git a/README.md b/README.md
index 3324209..f79149a 100644
--- a/README.md
+++ b/README.md
@@ -9,3 +9,10 @@ An oh-my-zsh theme.
 
 ## Usage
 REF: [Oh-My-Zsh External themes](https://github.com/ohmyzsh/ohmyzsh/wiki/External-themes)
+
+### Trouble Shooting
+
+#### macOS
+passsion.zsh-theme uses cmd ```gdate``` to get current time in milliseconds which is not installed default in macOS.
+
+run ```brew install coreutils;``` to get ```gdate```;
\ No newline at end of file
diff --git a/passion.zsh-theme b/passion.zsh-theme
index 7794ae7..086da82 100644
--- a/passion.zsh-theme
+++ b/passion.zsh-theme
@@ -1,4 +1,16 @@
 
+# gdate for macOS
+# REF: https://apple.stackexchange.com/questions/135742/time-in-milliseconds-since-epoch-in-the-terminal
+if [[ "$OSTYPE" == "darwin"* ]]; then
+    {
+        gdate
+    } || {
+        echo "\n$fg_bold[yellow]zsh theme passion needs gdate in coreutils:$reset_color"
+        echo "$fg_bold[green]brew install coreutils;\n$reset_color";
+    }
+fi
+
+
 # time
 function real_time() {
     local color="%{$fg_no_bold[cyan]%}";                    # color in PROMPT need format in %{XXX%} which is not same with echo