diff --git a/markdown.php b/markdown.php
index 7c74aac..1128353 100644
--- a/markdown.php
+++ b/markdown.php
@@ -2209,6 +2209,8 @@ class MarkdownExtra_Parser extends Markdown_Parser {
 		return " id=\"$attr\"";
 	}
 	function _doHeaders_callback_setext($matches) {
+		if ($matches[3] == '-' && preg_match('{^- }', $matches[1]))
+			return $matches[0];
 		$level = $matches[3]{0} == '=' ? 1 : 2;
 		$attr  = $this->_doHeaders_attr($id =& $matches[2]);
 		$block = "<h$level$attr>".$this->runSpanGamut($matches[1])."</h$level>";