diff --git a/extensions/spellcheck/hunspell/src/hunspell_alloc_hooks.h b/extensions/spellcheck/hunspell/src/hunspell_alloc_hooks.h
index 8c600744b05f..8cd83dbca565 100644
--- a/extensions/spellcheck/hunspell/src/hunspell_alloc_hooks.h
+++ b/extensions/spellcheck/hunspell/src/hunspell_alloc_hooks.h
@@ -47,9 +47,6 @@
  * allocated using C memory allocation functions.
  */
 
-// Prevent the standard macros from being redefined
-#define mozilla_mozalloc_macro_wrappers_h
-
 #include "mozilla/mozalloc.h"
 
 extern void HunspellReportMemoryAllocation(void*);
diff --git a/ipc/chromium/src/base/message_pump_qt.h b/ipc/chromium/src/base/message_pump_qt.h
index ccf403a4feba..48a956756ff9 100644
--- a/ipc/chromium/src/base/message_pump_qt.h
+++ b/ipc/chromium/src/base/message_pump_qt.h
@@ -5,11 +5,6 @@
 #ifndef BASE_MESSAGE_PUMP_QT_H_
 #define BASE_MESSAGE_PUMP_QT_H_
 
-#ifdef mozilla_mozalloc_macro_wrappers_h
-/* The "anti-header" */
-#  include "mozilla/mozalloc_undef_macro_wrappers.h"
-#endif
- 
 #include <qobject.h>
 
 #include "base/message_pump.h"
diff --git a/memory/mozalloc/moz.build b/memory/mozalloc/moz.build
index 191523e852a3..850e39d9b1c8 100644
--- a/memory/mozalloc/moz.build
+++ b/memory/mozalloc/moz.build
@@ -11,9 +11,7 @@ EXPORTS.mozilla += [
     'fallible.h',
     'mozalloc.h',
     'mozalloc_abort.h',
-    'mozalloc_macro_wrappers.h',
     'mozalloc_oom.h',
-    'mozalloc_undef_macro_wrappers.h',
 ]
 
 if CONFIG['MOZ_MSVC_STL_WRAP__RAISE'] or CONFIG['MOZ_MSVC_STL_WRAP__Throw']:
diff --git a/memory/mozalloc/mozalloc.cpp b/memory/mozalloc/mozalloc.cpp
index 5da9943726c0..f43e0bb63b9e 100644
--- a/memory/mozalloc/mozalloc.cpp
+++ b/memory/mozalloc/mozalloc.cpp
@@ -24,8 +24,6 @@
 #  define MOZALLOC_EXPORT __declspec(dllexport)
 #endif
 
-// Make sure that "malloc" et al. resolve to their libc variants.
-#define MOZALLOC_DONT_DEFINE_MACRO_WRAPPERS
 #include "mozilla/mozalloc.h"
 #include "mozilla/mozalloc_oom.h"  // for mozalloc_handle_oom
 
diff --git a/memory/mozalloc/mozalloc_macro_wrappers.h b/memory/mozalloc/mozalloc_macro_wrappers.h
deleted file mode 100644
index 465a58784f8b..000000000000
--- a/memory/mozalloc/mozalloc_macro_wrappers.h
+++ /dev/null
@@ -1,51 +0,0 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
- * vim: sw=4 ts=4 et :
- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_mozalloc_macro_wrappers_h
-#define mozilla_mozalloc_macro_wrappers_h
-
-
-/*
- * Make libc "allocating functions" never fail (return NULL).
- *
- * FIXME: use infallible allocators by default after 
- *   http://bugzilla.mozilla.org/show_bug.cgi?id=507249
- * lands.
- */
-#define free(_) moz_free(_)
-
-#define malloc(_) moz_malloc(_)
-
-#define calloc(_, __) moz_calloc(_, __)
-
-#define realloc(_, __) moz_realloc(_, __)
-
-/*
- * Note: on some platforms, strdup may be a macro instead of a function.
- * So we have to #undef it to avoid build warnings about redefining it.
- */
-#undef strdup
-#define strdup(_) moz_strdup(_)
-
-#if defined(HAVE_STRNDUP)
-#define strndup(_, __) moz_strndup(_, __)
-#endif
-
-#if defined(HAVE_POSIX_MEMALIGN)
-#define posix_memalign(_, __, ___) moz_posix_memalign(_, __, ___)
-#endif
-
-#if defined(HAVE_MEMALIGN)
-#define memalign(_, __) moz_memalign(_, __)
-#endif
-
-#if defined(HAVE_VALLOC)
-#define valloc(_) moz_valloc(_)
-#endif
-
-
-#endif /* ifndef mozilla_mozalloc_macro_wrappers_h */
diff --git a/memory/mozalloc/mozalloc_undef_macro_wrappers.h b/memory/mozalloc/mozalloc_undef_macro_wrappers.h
deleted file mode 100644
index 0ab5c28f9a09..000000000000
--- a/memory/mozalloc/mozalloc_undef_macro_wrappers.h
+++ /dev/null
@@ -1,44 +0,0 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
- * vim: sw=4 ts=4 et :
- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/*
- * This header is the "anti-header" for mozalloc_macro_wrappers.h.
- * Including it undefines all the macros defined by
- * mozalloc_macro_wrappers.h.
- */
-
-#ifndef mozilla_mozalloc_macro_wrappers_h
-#  error "mozalloc macro wrappers haven't been defined"
-#endif
-
-/*
- * This allows the wrappers to be redefined by including
- * mozalloc_macro_wrappers.h again 
- */
-#undef mozilla_mozalloc_macro_wrappers_h
-
-#undef free
-#undef malloc
-#undef calloc
-#undef realloc
-#undef strdup
-
-#if defined(HAVE_STRNDUP)
-#  undef strndup
-#endif
-
-#if defined(HAVE_POSIX_MEMALIGN)
-#  undef posix_memalign
-#endif
-
-#if defined(HAVE_MEMALIGN)
-#  undef memalign
-#endif
-
-#if defined(HAVE_VALLOC)
-#  undef valloc
-#endif
diff --git a/tools/jprof/stub/libmalloc.cpp b/tools/jprof/stub/libmalloc.cpp
index ea74941f2288..c68d65bf9eb8 100644
--- a/tools/jprof/stub/libmalloc.cpp
+++ b/tools/jprof/stub/libmalloc.cpp
@@ -37,8 +37,6 @@
 #include <errno.h>
 #include <dlfcn.h>
 
-#include "mozilla/mozalloc_undef_macro_wrappers.h"
-
 // Must define before including jprof.h
 void *moz_xmalloc(size_t size)
 {
diff --git a/xpcom/base/nscore.h b/xpcom/base/nscore.h
index b4f1489bbe62..c21c017ce7d9 100644
--- a/xpcom/base/nscore.h
+++ b/xpcom/base/nscore.h
@@ -17,7 +17,6 @@
 /* Definitions of functions and operators that allocate memory. */
 #if !defined(XPCOM_GLUE) && !defined(NS_NO_XPCOM) && !defined(MOZ_NO_MOZALLOC)
 #  include "mozilla/mozalloc.h"
-#  include "mozilla/mozalloc_macro_wrappers.h"
 #endif
 
 /**