diff --git a/dom/src/base/nsDOMException.cpp b/dom/src/base/nsDOMException.cpp
index 8a814d878dde..10019b5cbd2b 100644
--- a/dom/src/base/nsDOMException.cpp
+++ b/dom/src/base/nsDOMException.cpp
@@ -276,7 +276,7 @@ nsDOMException::GetData(nsISupports **aData)
 NS_IMETHODIMP
 nsDOMException::ToString(char **aReturn)
 {
-  *aReturn = nsCRT::strdup("foo");
+  *aReturn = nsnull;
 
   const ResultStruct *rs = NSResultToResultStruct(mResult);