diff --git a/src/Symfony/Component/HttpFoundation/Response.php b/src/Symfony/Component/HttpFoundation/Response.php
index 1d19a2ed82..882ac4d365 100644
--- a/src/Symfony/Component/HttpFoundation/Response.php
+++ b/src/Symfony/Component/HttpFoundation/Response.php
@@ -206,7 +206,7 @@ class Response
         $headers = $this->headers;
 
         if ($this->isInformational() || in_array($this->statusCode, array(204, 304))) {
-            $this->setContent('');
+            $this->setContent(null);
         }
 
         // Content-type based on the Request
@@ -234,7 +234,7 @@ class Response
         if ('HEAD' === $request->getMethod()) {
             // cf. RFC2616 14.13
             $length = $headers->get('Content-Length');
-            $this->setContent('');
+            $this->setContent(null);
             if ($length) {
                 $headers->set('Content-Length', $length);
             }
diff --git a/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php b/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
index 49642d4801..ec66dcd5fc 100644
--- a/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
+++ b/src/Symfony/Component/HttpKernel/HttpCache/HttpCache.php
@@ -581,7 +581,7 @@ class HttpCache implements HttpKernelInterface, TerminableInterface
     private function restoreResponseBody(Request $request, Response $response)
     {
         if ('HEAD' === $request->getMethod() || 304 === $response->getStatusCode()) {
-            $response->setContent('');
+            $response->setContent(null);
             $response->headers->remove('X-Body-Eval');
             $response->headers->remove('X-Body-File');