diff --git a/lib/HTTP/ConditionalGet.php b/lib/HTTP/ConditionalGet.php
index 8bfd0af..6087c04 100644
--- a/lib/HTTP/ConditionalGet.php
+++ b/lib/HTTP/ConditionalGet.php
@@ -317,7 +317,9 @@ class HTTP_ConditionalGet
         if (!isset($_SERVER['HTTP_IF_NONE_MATCH'])) {
             return false;
         }
-        $clientEtagList = $_SERVER['HTTP_IF_NONE_MATCH'];
+        $clientEtagList = PHP_VERSION_ID < 50400 && get_magic_quotes_gpc()
+            ? stripslashes($_SERVER['HTTP_IF_NONE_MATCH'])
+            : $_SERVER['HTTP_IF_NONE_MATCH'];
         $clientEtags = explode(',', $clientEtagList);
 
         $compareTo = $this->normalizeEtag($this->_etag);