1) I often have a bad taste in my mouth, and bad breath as well, I assume. This doesn't stem from poor hygiene: I brush my teeth at least three times a day, and usually more. I'm wondering if there is anything I can do about this. Could this be a symptom of some sort of nutritional deficiency? I think my diet is pretty bad, although I'm working pretty hard on getting more protein and eating less fat. I've also been nauseous a lot lately, and vomiting some. Could that be related?

2) Like many people, I often have an embarrassing bad breath. Listerine and other mouthwashes won't be of any help for this chronic problem. There are lots of products available to get rid of "volatile sulfur compounds (VSC)" - that supposedly cause this — and I just don't know which one I should try. Also, what's your opinion on tongue-brushing?

1) Which is better for you, tap or bottled water?

2) How bad is the water here in New York City? Do you recommend drinking filtered water, or does it really make a difference?

What is the significant difference between a product that is antiseptic and one that is antibacterial? All of the antiseptic mouthwashes I find have a great amount of alcohol in them. This can be very irritating to the mouth. I have found one that is alcohol free, but it says it is antibacterial.

Thanks for your help.

1) My girlfriend just saw her ob/gyn and was told that she has a mild yeast infection. Being that we are sexually active, is this something that I should be concerned about?

2) Can a guy get an infection if he has unprotected oral sex with a girl who has a yeast infection?

I'm a 21 year old woman with white lumpy vaginal discharge (odorless)...I thought it was thrush but after two courses of yeast infection cream it has not resolved...I have never had sex, so can't have an STD...I get bad pain in my lower back and sacro-iliac region with my period and with ovulation though I don't know if this is relevant...I'm embarrassed to see a health care professional about this and don't know if I'm just concerned over nothing...

So far I have been extremely impressed by your service. I trust you with a question which I know many people share: Are whitening toothpastes detrimental to the longevity of one's teeth?

I was told by my dentist that my teeth eroded, due to consumption of too much acidic food. I would like to know what kind of food causes tooth erosion. Do you have a list of these foods?

I have chronic yeast infections. My doctor basically said that I have a pH imbalance and to stock up on Mycelex or similar creams. This answer, to me, is unsatisfactory. There must be something I can do to keep my pH level in balance, or at least on the acidic side. Do lactobacillus and acidophilus tablets keep the vagina more acidic to prevent a yeast infection?

I’m having a burning sensation when I urinate and it still burns after I urinate. Also, I can’t urinate all the way and am continually having to go to the bathroom. I was diagnosed with kidney reflux when I was a child — could this be that?