diff --git a/src/Illuminate/Support/Str.php b/src/Illuminate/Support/Str.php
index 98e447f31ae1..9e84b3cd73da 100644
--- a/src/Illuminate/Support/Str.php
+++ b/src/Illuminate/Support/Str.php
@@ -637,10 +637,16 @@ public static function words($value, $words = 100, $end = '...')
      * @param  array  $options
      * @return string
      */
-    public static function markdown($string, array $options = [])
+    public static function markdown($string, array $options = [], array $extensions = [])
     {
         $converter = new GithubFlavoredMarkdownConverter($options);
 
+		$environment = $converter->getEnvironment();
+
+		foreach ($extensions as $extension) {
+			$environment->addExtension($extension);
+		}
+
         return (string) $converter->convert($string);
     }