diff --git a/rdf/tests/rdfcat/rdfcat.cpp b/rdf/tests/rdfcat/rdfcat.cpp
index 67cb63fc157..6e2d2d2b5f1 100644
--- a/rdf/tests/rdfcat/rdfcat.cpp
+++ b/rdf/tests/rdfcat/rdfcat.cpp
@@ -97,12 +97,11 @@ public:
     // nsISupports interface
     NS_DECL_ISUPPORTS
 
-    // nsIBaseStream interface
+    // nsIOutputStream interface
     NS_IMETHOD Close(void) {
         return NS_OK;
     }
 
-    // nsIOutputStream interface
     NS_IMETHOD Write(const char* aBuf, PRUint32 aCount, PRUint32 *aWriteCount) {
         PR_Write(PR_GetSpecialFD(PR_StandardOutput), aBuf, aCount);
         *aWriteCount = aCount;
diff --git a/rdf/tests/triplescat/triplescat.cpp b/rdf/tests/triplescat/triplescat.cpp
index 20f684b52fd..6371f1182af 100644
--- a/rdf/tests/triplescat/triplescat.cpp
+++ b/rdf/tests/triplescat/triplescat.cpp
@@ -95,12 +95,11 @@ public:
     // nsISupports interface
     NS_DECL_ISUPPORTS
 
-    // nsIBaseStream interface
+    // nsIOutputStream interface
     NS_IMETHOD Close(void) {
         return NS_OK;
     }
 
-    // nsIOutputStream interface
     NS_IMETHOD Write(const char* aBuf, PRUint32 aCount, PRUint32 *aWriteCount) {
         PR_Write(PR_GetSpecialFD(PR_StandardOutput), aBuf, aCount);
         *aWriteCount = aCount;
diff --git a/xpcom/io/nsIBaseStream.idl b/xpcom/io/nsIBaseStream.idl
deleted file mode 100644
index 12e4c5f0a17..00000000000
--- a/xpcom/io/nsIBaseStream.idl
+++ /dev/null
@@ -1,45 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is mozilla.org code.
- *
- * The Initial Developer of the Original Code is
- * Netscape Communications Corporation.
- * Portions created by the Initial Developer are Copyright (C) 1998
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
-
-#include "nsISupports.idl"
-
-[scriptable, uuid(6ccb17a0-e95e-11d1-beae-00805f8a66dc)]
-interface nsIBaseStream : nsISupports
-{
-    /** Close the stream. */
-    void close();
-};
diff --git a/xpcom/io/nsScriptableInputStream.cpp b/xpcom/io/nsScriptableInputStream.cpp
index 4a7960b1c07..30790de2115 100644
--- a/xpcom/io/nsScriptableInputStream.cpp
+++ b/xpcom/io/nsScriptableInputStream.cpp
@@ -41,14 +41,13 @@
 
 NS_IMPL_ISUPPORTS1(nsScriptableInputStream, nsIScriptableInputStream)
 
-// nsIBaseStream methods
+// nsIScriptableInputStream methods
 NS_IMETHODIMP
 nsScriptableInputStream::Close(void) {
     if (!mInputStream) return NS_ERROR_NOT_INITIALIZED;
     return mInputStream->Close();
 }
 
-// nsIScriptableInputStream methods
 NS_IMETHODIMP
 nsScriptableInputStream::Init(nsIInputStream *aInputStream) {
     if (!aInputStream) return NS_ERROR_NULL_POINTER;