No matter what your message says, just make sure you have one – it’s the polite and professional thing to so. To help you get started, we’ve put together some examples you can test, tweak, use, and share with colleagues.
On the other hand, there may be times where you’re so embedded in a project that you truly need to stay connected while you’re out. If that’s the case, say so clearly with a message like this: “I’m away but will be checking messages regularly, so don’t hesitate to contact me directly at any time.” Saying anything less than this may cause people to try to respect your time away and work around you, which in this case could create problems.

Then there was the occasional one who would do what Alison mentioned with the sickness excuses, and create a tale that read like a police report: “I must miss my deadline because, on the night of August 12, my 45-year-old sister was alone in her house when an intruder entered. He was a 6’1″ caucasian male wearing a black balaclava and carrying a candlestick. As my sister approached him, with the dog barking around her heels, she heard a distant car crash which led her to have a fatal … etc.” (This is not an actual excuse I received, just similar in detail to some of those that were submitted.) These ones I was pretty sure were a writing exercise, requiring time and effort that could have been put to better use on the actual assignment they had been given.
Oh you see, I do that on purpose. That way I can use the same OOO message internally and externally. Anyone within our company can find us in the global address book. Anyone outside our company who has done business with my department has my email address & my manager’s.