diff --git a/lib/plug/conn/utils.ex b/lib/plug/conn/utils.ex
index e2652477..a98d09d2 100644
--- a/lib/plug/conn/utils.ex
+++ b/lib/plug/conn/utils.ex
@@ -117,6 +117,9 @@ defmodule Plug.Conn.Utils do
       iex> content_type "*/*"
       :error
 
+      iex> content_type "something"
+      :error
+
   """
   @spec content_type(binary) :: {:ok, type :: binary, subtype :: binary, params} | :error
   def content_type(binary) do
@@ -162,6 +165,9 @@ defmodule Plug.Conn.Utils do
       iex> params(";")
       %{}
 
+      iex> params("foo=")
+      %{}
+
   """
   @spec params(binary) :: params
   def params(t) do