diff --git a/Data/Void.hs b/Data/Void.hs
--- a/Data/Void.hs
+++ b/Data/Void.hs
@@ -10,7 +10,12 @@
 -- Portability :  portable
 --
 ----------------------------------------------------------------------------
-module Data.Void (Void, absurd, vacuous, vacuousM) where
+module Data.Void
+  ( Void
+  , absurd
+  , vacuous
+  , vacuousM
+  ) where
 
 import Data.Ix
 import Control.Monad (liftM)
diff --git a/Data/Void/Unsafe.hs b/Data/Void/Unsafe.hs
new file mode 100644
--- /dev/null
+++ b/Data/Void/Unsafe.hs
@@ -0,0 +1,48 @@
+{-# LANGUAGE CPP #-}
+#if !defined(SAFE) && defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 702
+#define UNSAFE
+{-# LANGUAGE Unsafe #-}
+#endif
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  Data.Void.Unsafe
+-- Copyright   :  (C) 2008-2012 Edward Kmett
+-- License     :  BSD-style (see the file LICENSE)
+--
+-- Maintainer  :  Edward Kmett <ekmett@gmail.com>
+-- Stability   :  provisional
+-- Portability :  portable
+--
+----------------------------------------------------------------------------
+module Data.Void.Unsafe
+  ( unsafeVacuous
+  , unsafeVacuousM
+  ) where
+
+import Data.Void
+
+#ifdef UNSAFE
+import Unsafe.Coerce
+#endif
+
+-- | If 'Void' is uninhabited than any 'Functor' that holds only values of the type 'Void'
+-- is holding no values.
+--
+-- This is only safe for valid functors that do not perform GADT-like analysis on the argument.
+unsafeVacuous :: Functor f => f Void -> f a
+#ifdef UNSAFE
+unsafeVacuous = unsafeCoerce
+#else
+unsafeVacuous = fmap absurd
+#endif
+
+-- | If 'Void' is uninhabited then any 'Monad' that holds values of type 'Void'
+-- is holding no values.
+--
+-- This is only safe for valid monads that do not perform GADT-like analysis on the argument.
+unsafeVacuousM :: Monad m => m Void -> m a
+#ifdef UNSAFE
+unsafeVacuousM = unsafeCoerce
+#else
+unsafeVacuousM m = m >>= return . absurd
+#endif
diff --git a/void.cabal b/void.cabal
--- a/void.cabal
+++ b/void.cabal
@@ -1,6 +1,6 @@
 name:          void
 category:      Data Structures
-version:       0.5.10
+version:       0.5.11
 license:       BSD3
 cabal-version: >= 1.6
 license-file:  LICENSE
@@ -20,16 +20,23 @@
   type: git
   location: git://github.com/ekmett/void.git
 
+flag safe
+  manual: True
+  default: False
+
 library
-  extensions:
-    CPP
   exposed-modules:
     Data.Void
+    Data.Void.Unsafe
+
   build-depends:
-    base >= 3 && < 10,
-    semigroups >= 0.8.2 && < 0.9
+    base       >= 3 && < 10,
+    semigroups >= 0.8.2
 
   ghc-options: -Wall
+
+  if flag(safe)
+    cpp-options: -DSAFE
 
   if impl(ghc)
     extensions: DeriveDataTypeable