Serious problem, I have a friend who has a... er.. 'hygene problem'... help?

Sometimes you just gotta be honest. Be gentle though...tell her that you've noticed that she isn't the cleanest person in the world. Maybe she doesn't have access to a washer/dryer (offer yours or invite her to tag along when you go to the laundry mat). If she's your friend and you want to keep her as one, just be honest...in a nice way. Some people were just never taught about some this stuff...sadly, I know some ppl like that.