diff --git a/composer.json b/composer.json
index 41b089f..9c3472f 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,7 @@
 		}
 	],
 	"require" : {
-		"php" : ">=5.3.9",
+		"php" : ">=5.4.6",
 		"mouf/mouf-installer" : "~2.0.1",
 		"mouf/mouf-validators-interface" : "~2.0",
 		"container-interop/container-interop" : "~1.0",
diff --git a/src/Mouf/Reflection/MoufReflectionParameter.php b/src/Mouf/Reflection/MoufReflectionParameter.php
index a698c0b..0a5c009 100644
--- a/src/Mouf/Reflection/MoufReflectionParameter.php
+++ b/src/Mouf/Reflection/MoufReflectionParameter.php
@@ -207,6 +207,9 @@ public function toJson() {
     			// In some cases, the call to getDefaultValue can log NOTICES
     			// in particular if an undefined constant is used as default value.
     			ob_start();
+    			if ($this->isDefaultValueConstant() && !defined($this->getDefaultValueConstantName())) {
+    			    throw new \Exception('Constant "'.$this->getDefaultValueConstantName().'" does not exist.');
+                }
     			$result['default'] = $this->getDefaultValue();
     			$possibleError = ob_get_clean();
     			if ($possibleError) {