DEAR DR. DONOHUE: Bad breath is ruining my life. I see people step back when I talk to them, and I know it’s because of my breath. I constantly rinse with mouthwash. Obviously it’s not working. Where do I turn? – L.G.

ANSWER: Turn to your dentist. In 85 percent of people with bad breath, the cause will be found in the mouth.

Do you have an honest friend? Enlist that person to check your breath. Close your mouth and stop breathing for a short time. Position your friend in front of your mouth and exhale through it. Your friend can tell you without doubt that the exhaled mouth air is or isn’t unpleasant. If there is doubt, close your mouth and exhale forcibly through the nose. If that exhaled air is unpleasant, then the problem lies in the nose or sinuses.

Most often, the trouble comes from the degradation of food particles by mouth bacteria that generate sulfur-containing gases. Those gases are foul-smelling. You have to adopt an all-out attack on those bacteria to clear the air. Brush after eating, and floss daily. Brush your tongue as far back as you can. The back of the tongue is often where these bacteria live. You would do an even better job with a plastic tongue cleaner found in drugstores. Don’t rub the tongue raw. “Gentle” is the word.

If you have a dry mouth, keep a water bottle with you for constant sipping. Chew sugarless gum.

If the problem lies in the nose or sinuses, your dentist can direct you to an ear, nose and throat doctor.

I have made it sound like all halitosis is curable by careful oral hygiene. It isn’t. Bad breath can come from lung conditions, failing kidneys or liver cirrhosis. Even heartburn has been known to cause it. But start with the dentist and with scrupulous mouth care before launching into the rarer causes of halitosis.

DEAR DR. DONOHUE: Is Viagra off-limits for an 85-year-old? My wife and I are sexually active, but I haven’t been able to perform like I used to, and sometimes I can’t perform at all. I don’t take any medicine, and I have enjoyed good health. I have never been inside a hospital. I do have a doctor whom I see yearly. Will he think I’m crazy if I bring this up? – S.K.

ANSWER: Age is no barrier to taking Viagra or the other related medicines. The doctor won’t think you’re the least bit crazy if you ask for a prescription of Viagra.

Medicines with nitrates – drugs used mostly for the treatment of angina chest pain – can’t be used with Viagra, and some blood pressure medicines are not compatible with it. You take no medicines. You’re not barred from taking Viagra.

Let me mention one consideration that you ought to discuss with your doctor. One big cause of erectile dysfunction is clogging of the arteries that supply the penis. If those arteries are clogged, other arteries are most likely affected too. Heart arteries, brain arteries and arteries to the leg muscles are the ones I’m referring to. Your doctor will want to check the state of your general circulation.

DEAR DR. DONOHUE: My temperature is always below normal. It hovers around 97.2 F (36.2 C). What does this mean? I feel tired a lot. – M.C.

ANSWER: Contrary to what has been pounded into our heads, normal body temperature is not 98.6 F (37 C). It varies from person to person and from hour to hour. It rises as we are more active, and it drops when we rest. It dips to its lowest point in the early-morning hours and reaches a high in the late afternoon or early evening.

Stop taking your temperature. Yours is not making your feel tired. You have to look elsewhere for an explanation of that.

DEAR DR. DONOHUE: I am 66 and have a great memory. I believe it’s due to my having given up booze 25 years ago. If you have ever gotten drunk, I bet you had some memory loss at the time. Alcohol destroys brain cells. – T.M.

ANSWER: Alcohol in excess destroys brain cells and memory. But moderate use of alcohol can enhance health, especially heart and artery health. “Moderate” means no more than two drinks a day for a man and one for a woman.

DEAR DR. DONOHUE: I am 77 and in good health. I take medicine for high blood pressure.

My problem is my heartbeat. It is very slow. When I get up in the morning or when I sit for too long, it goes down to the 30s. If I get up, it rises to 60. Is this something to be concerned about? I have taken a treadmill test, and the doctor said I did well. What do you think? – C.W.

ANSWER: I think 30 beats a minute is way too slow a heart rate. Aren’t you dizzy or tired, or don’t you feel faint when the rate drops so low. With such a slow beat, it’s difficult to supply the brain with sufficient blood. You need to wear a heart monitor, one that records every heartbeat for one to three days. I’d go back to the doctor for more tests.

What is your blood pressure medicine? It might be the cause.

The booklet on heartbeat irregularities covers this subject in depth. Readers can order a copy by writing: Dr. Donohue – No. 107, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com