diff --git a/extension/src/main/java/de/jeremystartm/pickshadow/api/translation/LanguageString.java b/extension/src/main/java/de/jeremystartm/pickshadow/api/translation/LanguageString.java
index 5edb4d3..b679d7e 100644
--- a/extension/src/main/java/de/jeremystartm/pickshadow/api/translation/LanguageString.java
+++ b/extension/src/main/java/de/jeremystartm/pickshadow/api/translation/LanguageString.java
@@ -82,4 +82,7 @@ public enum LanguageString {
 
     // Event for chat messages
     CHATMESSAGE_SERVER,
+
+    // Event for chat commands
+    CHATCOMMAND_ERROR_NAMESPACE
 }
diff --git a/extension/src/main/java/de/jeremystartm/pickshadow/listener/ChatListener.java b/extension/src/main/java/de/jeremystartm/pickshadow/listener/ChatListener.java
index d4b4da9..40d85ab 100644
--- a/extension/src/main/java/de/jeremystartm/pickshadow/listener/ChatListener.java
+++ b/extension/src/main/java/de/jeremystartm/pickshadow/listener/ChatListener.java
@@ -51,4 +51,17 @@ public final class ChatListener implements Listener {
                 ).append(MiniMessage.miniMessage().deserialize(MiniMessage.miniMessage().serialize(event.originalMessage()).replace("\\<", "<")))
         );
     }
+
+    /**
+     * Handles chat commands.
+     *
+     * @since v1-release0
+     */
+    @EventHandler(priority = EventPriority.LOWEST, ignoreCancelled = true)
+    public void handleChatCommand(@NotNull PlayerCommandPreprocessEvent event) {
+        if (event.getMessage().split(" ")[0].contains(":")) {
+            event.setCancelled(true);
+            event.getPlayer().sendRichMessage(TranslationManager.get(LanguageString.CHATCOMMAND_ERROR_NAMESPACE, event.getPlayer(), true));
+        }
+    }
 }
diff --git a/extension/src/main/resources/translations/de.json b/extension/src/main/resources/translations/de.json
index 62c9a93..9011844 100644
--- a/extension/src/main/resources/translations/de.json
+++ b/extension/src/main/resources/translations/de.json
@@ -30,4 +30,6 @@
   "HOME_NORESPAWN": "<error>Du hast keinen gültigen Respawnpunkt.</error>\n<error>Stelle sicher, dass dein Bett oder Respawn Anker nicht abgebaut oder behindert ist.</error>",
 
   "TOGGLEDOWNFALL": "Niederschlag umgestellt",
+
+  "CHATCOMMAND_ERROR_NAMESPACE": "<error>Namespaces zu verwenden ist nicht erlaubt, da es verwendet werden kann um Sicherheitsmaßnahmen zu umgehen.</error>"
 }
diff --git a/extension/src/main/resources/translations/en.json b/extension/src/main/resources/translations/en.json
index d985b89..429b0a7 100644
--- a/extension/src/main/resources/translations/en.json
+++ b/extension/src/main/resources/translations/en.json
@@ -45,4 +45,6 @@
   "TOGGLEDOWNFALL": "Toggled downfall",
 
   "CHATMESSAGE_SERVER": "<mention>%sender%</mention> <#d60532>»</#d60532> ",
+
+  "CHATCOMMAND_ERROR_NAMESPACE": "<error>Using namespaces is not allowed, as it may be used to circumvent security measures.</error>"
 }