Inappropriate workplace emails take many forms, ranging from personal correspondence that doesn't belong in a business environment to those that are rude, threatening or sexually suggestive. Regardless of what makes the email inappropriate, if you are the recipient of such an email from a co-worker, you should take immediate action. Your response will depend, to some extent, on how inappropriate the email is, but if you confront your co-worker in an acceptable manner, you'll be more likely to successfully resolve this unpleasant situation.
Wait until your anger subsides before you confront your co-worker, especially if the email caused you a great deal of emotional upset, but don't wait too long. It's best to address the email within a day of when it was sent, but it's important to be in control of your emotions when you do bring the subject up.
Make an appointment with your co-worker. It's best if you say that you'd like to arrange a time to discuss a sensitive issue in private. You can request this time in an email, by phone or in person.
Prepare an outline of the main points you want to cover in your conversation, but don't prepare a whole speech. You want to sound authentic and keep the tone informal -- rehearsing every word or memorizing a speech will not accomplish this.
Set a friendly tone for the conversation. Start with a neutral comment rather than an outright accusation. Try to be supportive rather than critical.
Remember that your goal is to get your co-worker to realize that he made an error by sending the email and to ensure he won't do it again. If you keep your tone friendly and supportive, he is more likely to be receptive to what you are saying.
Ask questions and listen to the answers. This demonstrates that you are not just lashing out but that you are genuinely striving for a reasonable resolution.
Speak with tact and diplomacy. You want your co-worker to hear what you have to say -- if you communicate with respect and allow him to preserve his dignity, he is more likely to listen to your points.
Focus on the details of the email. For example, if your co-worker used capital letters throughout, point out how that suggests angry shouting.
Remind your co-worker that most employers have access to email accounts. Inform him that it could be a "career-limiting move" to send inappropriate emails that may be read by his supervisors. This will help project an air of caring on your part.
End the conversation on a positive note by summarizing what was said and your hope that this situation won't be repeated. Close with a comment on a new, non-threatening subject to help ease the tension next time you interact with this co-worker.