diff --git a/flask_cors/extension.py b/flask_cors/extension.py
index cfeca73..745e1b3 100644
--- a/flask_cors/extension.py
+++ b/flask_cors/extension.py
@@ -61,7 +61,11 @@ class CORS(object):
     :param origins:
         The origin, or list of origins to allow requests from.
         The origin(s) may be regular expressions, case-sensitive strings,
-        or else an asterisk
+        or else an asterisk.
+
+        :note: origins must include the schema and the port (if not port 80),
+        e.g.,
+        `CORS(app, origins=["http://localhost:*", "https://example.com"])`.
 
         Default : '*'
     :type origins: list, string or regex