diff --git a/witherable/src/Witherable.hs b/witherable/src/Witherable.hs
index 964a854..d6ee553 100644
--- a/witherable/src/Witherable.hs
+++ b/witherable/src/Witherable.hs
@@ -190,6 +190,7 @@ instance Witherable Maybe where
 
 instance Filterable Option where
   mapMaybe f = (>>= Option . f)
+  drain _ = Option Nothing
   {-# INLINE mapMaybe #-}
 
 instance Witherable Option where
@@ -207,6 +208,9 @@ instance Monoid e => Filterable (Either e) where
   mapMaybe f (Right a) = maybe (Left mempty) Right $ f a
   {-# INLINABLE mapMaybe #-}
 
+  drain (Left e)  = Left e
+  drain (Right _) = Left mempty
+
 instance Monoid e => Witherable (Either e) where
   wither _ (Left e) = pure (Left e)
   wither f (Right a) = fmap (maybe (Left mempty) Right) (f a)