diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,12 @@
+# 1.4.5
+* fix: MonadPlus lows of ApiaryT Monad
+
+# 1.4.4
+* use wai-extra to parse request body
+
+# 1.4.3
+* ghc-7.10 compatible
+
 # 1.4.2
 * fix: remove async from API document
 
diff --git a/apiary.cabal b/apiary.cabal
--- a/apiary.cabal
+++ b/apiary.cabal
@@ -1,5 +1,5 @@
 name:                apiary
-version:             1.4.4
+version:             1.4.5
 synopsis:            Simple and type safe web framework that generate web API documentation.
 description:
   Simple and type safe web framework that can be automatically generate API documentation.
diff --git a/src/Control/Monad/Apiary/Action/Internal.hs b/src/Control/Monad/Apiary/Action/Internal.hs
--- a/src/Control/Monad/Apiary/Action/Internal.hs
+++ b/src/Control/Monad/Apiary/Action/Internal.hs
@@ -258,7 +258,7 @@
 
 data Action a 
     = Continue ActionState a
-    | Pass
+    | Pass (Maybe RequestBody)
     | Stop Wai.Response
 
 newtype ActionT exts prms m a = ActionT { unActionT :: forall b. 
@@ -280,7 +280,7 @@
         => (Dict.Dict prms -> ActionEnv exts -> ActionState -> m (Action a))
         -> ActionT exts prms m a
 actionT f = ActionT $ \dict env !st cont -> f dict env st >>= \case
-    Pass            -> return Pass
+    Pass b          -> return $ Pass b
     Stop s          -> return $ Stop s
     Continue !st' a -> cont a st'
 {-# INLINE actionT #-}
@@ -298,7 +298,7 @@
 execActionT :: ApiaryConfig -> Extensions exts -> Documents -> ActionT exts '[] IO () -> Wai.Application
 execActionT config exts doc m request send = 
     runActionT m Dict.emptyDict (ActionEnv config request doc exts) (initialState config) >>= \case
-        Pass         -> notFound config request send
+        Pass _       -> notFound config request send
         Stop s       -> send s
         Continue r _ -> send $ toResponse r
 
@@ -355,11 +355,11 @@
     {-# INLINE (<|>) #-}
 
 instance Monad m => MonadPlus (ActionT exts prms m) where
-    mzero = ActionT $ \_ _ _ _ -> return Pass
+    mzero = ActionT $ \_ _ !st _ -> return $ Pass (actionReqBody st)
     mplus m n = ActionT $ \dict e !s cont -> unActionT m dict e s cont >>= \case
         Continue !st a -> return $ Continue st a
         Stop stp       -> return $ Stop stp
-        Pass           -> unActionT n dict e s cont
+        Pass b         -> unActionT n dict e s { actionReqBody = b } cont
     {-# INLINE mzero #-}
     {-# INLINE mplus #-}
 
diff --git a/tests/Application.hs b/tests/Application.hs
--- a/tests/Application.hs
+++ b/tests/Application.hs
@@ -14,6 +14,7 @@
 import Control.Monad.Identity(Identity(..))
 
 import Web.Apiary
+import Control.Monad.Apiary.Action
 import Network.Wai(Request)
 import qualified Network.Wai.Test as WT
 import qualified Network.Wai as Wai
@@ -34,13 +35,22 @@
                    | otherwise        = r { Wai.httpVersion = HTTP.http11 }
 --------------------------------------------------------------------------------
 
-assertRequest :: Int -> (Maybe S.ByteString) -> L.ByteString -> Application -> Request -> IO ()
-assertRequest sc ct body app req = flip WT.runSession app $ do
-    res <- WT.request req
+assertSRequest :: Int                -- ^ expected status code
+               -> Maybe S.ByteString -- ^ expected content type
+               -> L.ByteString       -- ^ expected request body
+               -> Application -> WT.SRequest -> IO ()
+assertSRequest sc ct body app req = flip WT.runSession app $ do
+    res <- WT.srequest req
     WT.assertBody body res
     WT.assertStatus sc res
     maybe (return ()) (flip WT.assertContentType res) ct
 
+assertRequest :: Int                -- ^ expected status code
+              -> Maybe S.ByteString -- ^ expected content type
+              -> L.ByteString       -- ^ expected request body
+              -> Application -> Request -> IO ()
+assertRequest sc ct body app req = assertSRequest sc ct body app (WT.SRequest req "")
+
 assertPlain200 :: L.ByteString -> Application -> Request -> IO ()
 assertPlain200 = assertRequest 200 (Just "text/plain")
 
@@ -326,6 +336,30 @@
 
 --------------------------------------------------------------------------------
 
+-- https://github.com/philopon/apiary/issues/17
+
+issue17App :: Application
+issue17App = runApp $ do
+    root $ do
+        method GET . ([key|foo|] =: pInt) . action $ do
+            foo <- param [key|foo|]
+            showing foo
+
+        method POST . action $ do
+            ps <- getReqBodyParams
+            showing ps
+
+issue17Test :: TestTree
+issue17Test = testGroup "issue17" $ map ($ issue17App)
+    [ testReq "GET /"          . assert404
+    , testReq "GET /?foo=test" . assert404
+    , testReq "GET /?foo=12"   . assertPlain200 "12"
+    , \app -> testReq "POST /" $ \req -> assertSRequest 200 Nothing "[(\"foo\",\"12\")]" app
+      (WT.SRequest req { Wai.requestHeaders = ("Content-Type", "application/x-www-form-urlencoded") : Wai.requestHeaders req} "foo=12")
+    ]
+
+--------------------------------------------------------------------------------
+
 test :: TestTree
 test = testGroup "Application"
     [ helloWorldAllTest
@@ -338,5 +372,6 @@
     , stopTest
     , acceptTest
     , multipleFilter1Test
+    , issue17Test
     ]