What are common pitfalls when using mod_rewrite for multiple variables in PHP?

Common pitfalls when using mod_rewrite for multiple variables in PHP include not properly capturing all variables in the RewriteRule and not correctly passing the variables to the PHP script. To solve this, make sure to use the QSA flag in the RewriteRule to append query string parameters, and access the variables in your PHP script using $_GET.

RewriteEngine On
RewriteRule ^page/([^/]+)/([^/]+)$ index.php?page=$1&category=$2 [QSA]
```

In your PHP script (index.php), you can access the variables like this:

```php
$page = $_GET['page'];
$category = $_GET['category'];