diff --git a/Michelf/MarkdownExtra.php b/Michelf/MarkdownExtra.php
index 9a4be84..32eca11 100644
--- a/Michelf/MarkdownExtra.php
+++ b/Michelf/MarkdownExtra.php
@@ -1645,7 +1645,7 @@ class MarkdownExtra extends \Michelf\Markdown {
 	 */
 	protected function doFootnotes($text) {
 		if (!$this->in_anchor) {
-			$text = preg_replace('{\[\^(.+?)\]}', "F\x1Afn:\\1\x1A:", $text);
+			$text = preg_replace('{\[\^(\S+?)\]}', "F\x1Afn:\\1\x1A:", $text);
 		}
 		return $text;
 	}