Edit the output of wp_widget_rss_output()

I want to show rss feed in my dashboard widget, i use this code:

wp_widget_rss_output(array(
    'url'           => 'http://www.example.com/',
    'title'         => __( 'Some Title' ),
    'items'         => 1,
    'show_summary'  => 1,
    'show_author'   => 0,
    'show_date'     => 0
));

but after the ‘show_summary’ wordpress addes ‘[…]’. How do i remove it?

You can’t, because the wp_widget_rss_output() prints its output. If you don’t want to display ‘[…]’ copy that function in your functions.php, rename it and remove the code that adds the ‘[…]’ to the summary. You can also create a plugin with this code thus making independent from your theme.