When you're in close quarters with a friend or co-worker and you repeatedly find that their personal hygiene isn't quite up to par, should you say something?
The best way is to approach this in the same manner you would want someone to address you if the situation were reversed. And chances are, you'd want to know if your personal body odor was clearing the room!
If you go to the person discreetly and with the sole intention of being helpful and kind, you should be good to go. Just be aware and prepared for all the possible responses.