diff --git a/README.md b/README.md
index ee2f9d6..36259bb 100644
--- a/README.md
+++ b/README.md
@@ -24,8 +24,12 @@ npm install punycode --save
 
 In [Node.js](https://nodejs.org/):
 
+> ⚠️ Note that userland modules don't hide core modules.
+> For example, `require('punycode')` still imports the deprecated core module even if you executed `npm install punycode`.
+> Use `require('punycode/')` to import userland modules rather than core modules.
+
 ```js
-const punycode = require('punycode');
+const punycode = require('punycode/');
 ```
 
 ## API