   said, a variable defined in a macro cannot affect the scope
   where the macro is included.
 
+  The option `hygiene` can turn off all the hygiene mechanisms
+  defined below. However, they can also be changed in a one by
+  one basis.
+
   ### Hygiene in variables
 
   Consider the following example:

      a #=> 10

  In the example above, `a` returns 10 even if the macro
  is apparently setting it to 1 because the variables defined
  in the macro does not affect the context the macro is
  executed. If you want to set or get a variable, you can do
  it with the help of the `var!` macro:

      defmodule NoHygiene do
        defmacro interference do

  * `:location` - When set to `:keep`, keeps the current line and file on quotes.
                  Read the Stacktrace information section below for more information;
  * `:expand_aliases` - When false, do not expand aliases;
  * `:var_context` - The context for quoted variables. Defaults to the current module;

  ## Macro literals

