diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 77a628e82b5e..54a0a80536be 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -2767,8 +2767,10 @@ os_prompt%</pre>
           Otherwise, some other point in time is chosen. It is also
           guaranteed that subsequent calls to this BIF returns
           continuously increasing values. Hence, the return value from
-          <c>now()</c> can be used to generate unique time-stamps. It
-          can only be used to check the local time of day if
+          <c>now()</c> can be used to generate unique time-stamps,
+          and if it is called in a tight loop on a fast machine
+          the time of the node can become skewed.</p>
+        <p>It can only be used to check the local time of day if
           the time-zone info of the underlying operating system is
           properly configured.</p>
       </desc>
diff --git a/lib/stdlib/doc/src/timer.xml b/lib/stdlib/doc/src/timer.xml
index 0b6807dd6c79..034fff3c259e 100644
--- a/lib/stdlib/doc/src/timer.xml
+++ b/lib/stdlib/doc/src/timer.xml
@@ -211,7 +211,8 @@
       </type>
       <desc>
         <p>Evaluates <c>apply(Module, Function, Arguments)</c> and measures
-          the elapsed real time. Returns <c>{Time, Value}</c>, where 
+          the elapsed real time as reported by <c>now/0</c>.
+          Returns <c>{Time, Value}</c>, where 
           <c>Time</c> is the elapsed real time in <em>microseconds</em>,
           and <c>Value</c> is what is returned from the apply.</p>
       </desc>