diff --git a/servant-client-core/src/Servant/Client/Core.hs b/servant-client-core/src/Servant/Client/Core.hs
index 6d216d1f..822df161 100644
--- a/servant-client-core/src/Servant/Client/Core.hs
+++ b/servant-client-core/src/Servant/Client/Core.hs
@@ -225,11 +225,10 @@ instance OVERLAPPABLE_
       { requestAccept = fromList $ toList accept
       , requestMethod = method
       }
-    case mimeUnrender (Proxy :: Proxy ct) $ responseBody response of
-      Left err -> throwError $ DecodeFailure (pack err) response
-      Right val -> return val
-      where method = reflectMethod (Proxy :: Proxy method)
-            accept = contentTypes (Proxy :: Proxy ct)
+    response `decodedAs` (Proxy :: Proxy ct)
+    where
+      accept = contentTypes (Proxy :: Proxy ct)
+      method = reflectMethod (Proxy :: Proxy method)
 
 instance OVERLAPPING_
   ( RunClient m, ReflectMethod method
diff --git a/servant-client-core/src/Servant/Client/Core/Internal/Class.hs b/servant-client-core/src/Servant/Client/Core/Internal/Class.hs
index 0428fcb8..37287fd9 100644
--- a/servant-client-core/src/Servant/Client/Core/Internal/Class.hs
+++ b/servant-client-core/src/Servant/Client/Core/Internal/Class.hs
@@ -1,11 +1,44 @@
 {-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE ScopedTypeVariables   #-}
+{-# LANGUAGE TypeFamilies          #-}
+{-# LANGUAGE OverloadedStrings          #-}
 {-| Types for possible backends to run client-side `Request` queries -}
 module Servant.Client.Core.Internal.Class where
 
-import           Control.Monad.Error.Class            (MonadError)
-import           Servant.Client.Core.Internal.Request (Request, Response,
-                                                       ServantError)
+import           Control.Monad                        (unless)
+import           Control.Monad.Error.Class            (MonadError, throwError)
+import           Data.Proxy                           (Proxy)
+import qualified Data.Text                            as T
+import           Network.HTTP.Media                   (MediaType, matches,
+                                                       parseAccept, (//))
+import           Servant.API                          (MimeUnrender,
+                                                       contentTypes,
+                                                       mimeUnrender)
+import           Servant.Client.Core.Internal.Request (Request, Response (..),
+                                                       ServantError (..))
+import Data.Foldable (toList)
 
 class (MonadError ServantError m) => RunClient m where
+  -- | How to make a request.
   runRequest :: Request -> m Response
+
+checkContentTypeHeader :: RunClient m => Response -> m MediaType
+checkContentTypeHeader response =
+  case lookup "Content-Type" $ toList $ responseHeaders response of
+    Nothing -> pure $ "application"//"octet-stream"
+    Just t -> case parseAccept t of
+      Nothing -> throwError $ InvalidContentTypeHeader response
+      Just t' -> pure t'
+
+decodedAs :: forall ct a m. (MimeUnrender ct a, RunClient m)
+  => Response -> Proxy ct -> m a
+decodedAs response contentType = do
+  responseContentType <- checkContentTypeHeader response
+  unless (any (matches responseContentType) accept) $
+    throwError $ UnsupportedContentType responseContentType response
+  case mimeUnrender contentType $ responseBody response of
+    Left err -> throwError $ DecodeFailure (T.pack err) response
+    Right val -> return val
+  where
+    accept = toList $ contentTypes contentType
diff --git a/servant-client/test/Servant/ClientSpec.hs b/servant-client/test/Servant/ClientSpec.hs
index 46835495..3a5ef1f6 100644
--- a/servant-client/test/Servant/ClientSpec.hs
+++ b/servant-client/test/Servant/ClientSpec.hs
@@ -24,7 +24,7 @@
 {-# OPTIONS_GHC -fno-warn-name-shadowing #-}
 
 #include "overlapping-compat.h"
-module Servant.ClientSpec where
+module Servant.ClientSpec (spec) where
 
 import           Prelude                                    ()
 import           Prelude.Compat
@@ -35,18 +35,13 @@ import           Control.Concurrent                         (ThreadId, forkIO,
 import           Control.Exception                          (bracket)
 import           Control.Monad.Error.Class                  (throwError)
 import           Data.Aeson
-import qualified Data.ByteString.Lazy                       as BS
 import           Data.Char                                  (chr, isPrint)
-import           Data.Foldable                              (toList)
 import           Data.Foldable                              (forM_)
-import           Data.Maybe                                 (isJust)
 import           Data.Monoid                                hiding (getLast)
 import           Data.Proxy
-import           Data.Sequence                              (findIndexL)
 import qualified Generics.SOP                               as SOP
 import           GHC.Generics                               (Generic)
 import qualified Network.HTTP.Client                        as C
-import           Network.HTTP.Media
 import qualified Network.HTTP.Types                         as HTTP
 import           Network.Socket
 import qualified Network.Wai                                as Wai
@@ -96,8 +91,8 @@ spec = describe "Servant.Client" $ do
 -- * test data types
 
 data Person = Person
-  { name :: String
-  , age  :: Integer
+  { _name :: String
+  , _age  :: Integer
   } deriving (Eq, Show, Generic)
 
 instance ToJSON Person
@@ -233,14 +228,14 @@ genAuthAPI = Proxy
 type instance AuthServerData (AuthProtect "auth-tag") = ()
 type instance AuthClientData (AuthProtect "auth-tag") = ()
 
-genAuthHandler :: AuthHandler Request ()
+genAuthHandler :: AuthHandler Wai.Request ()
 genAuthHandler =
-  let handler req = case lookup "AuthHeader" (toList $ requestHeaders req) of
+  let handler req = case lookup "AuthHeader" (Wai.requestHeaders req) of
         Nothing -> throwError (err401 { errBody = "Missing auth header" })
         Just _ -> return ()
   in mkAuthHandler handler
 
-genAuthServerContext :: Context '[ AuthHandler Request () ]
+genAuthServerContext :: Context '[ AuthHandler Wai.Request () ]
 genAuthServerContext = genAuthHandler :. EmptyContext
 
 genAuthServer :: Application
@@ -297,6 +292,7 @@ genericClientServer = serve (Proxy :: Proxy GenericClientAPI) (
 manager' :: C.Manager
 manager' = unsafePerformIO $ C.newManager C.defaultManagerSettings
 
+runClient :: ClientM a -> BaseUrl -> IO (Either ServantError a)
 runClient x baseUrl' = runClientM x (ClientEnv manager' baseUrl')
 
 sucessSpec :: Spec
@@ -344,8 +340,6 @@ sucessSpec = beforeAll (startWaiApp server) $ afterAll endWaiApp $ do
         Right r -> do
           responseStatusCode r `shouldBe` HTTP.status200
           responseBody r `shouldBe` "rawSuccess"
-          findIndexL (\x -> fst x == HTTP.hContentType) (responseHeaders r)
-            `shouldSatisfy` isJust
 
     it "Servant.API.Raw should return a Left in case of failure" $ \(_, baseUrl) -> do
       res <- runClient (getRawFailure HTTP.methodGet) baseUrl