DEAR DR. DONOHUE: I remember reading in the past that constant ringing in the ears is or could be a symptom of a physical problem. Since it did not pertain to me then, I relegated the information to a dim corner of my not-so-good-anymore memory bank. Now I have the problem. Can you fine tune my memory on this? - E.G.

ANSWER: I'll try. For millions of us, it's a buzzing, popping, ear ringing world. It's called tinnitus, the Latin for "ringing."The cause can be as mundane as earwax buildup, or it can be as significant as a hearing nerve tumor. Thus, we can never dismiss the symptoms out of hand.

Older people have the problem, although I must say we are seeing more younger ones, those who have listened to too much highly amplified rock music. In others, alcohol, nicotine and caffeine can augment the cacophony, as can drugs, like aspirin.

Some find relief through use of a hearing aid device that produces a masking sound to permit sleep at night. We can expect feedback mail telling how others have coped. I've painted this problem in broad strokes. Report the symptoms and let your doctor fine tune the details of your individual problem.

DEAR DR. DONOHUE: I've been waiting for a discussion of Guillain-Barre syndrome. How common is it? Does it return? - N.T.

ANSWER: We'll call it GB for short. This involves a sudden unexplained swelling of the insulation material around nerves. Nerve transmission to muscles is cut off, causing weakness.

GB symptoms usually start in the legs. Weakness spreads upward to the hips, even to the face and breathing muscles.

It all takes place over days or weeks, with recovery occurring two to four weeks later. How serious it is depends on how many muscles are involved and how extensively. Some have mild symptoms, while others require close support, as with mechanical lung ventilation.

Most recover, although I must report that 10 to 20 percent are left with residual muscle weakness, the severity of which depends again on the extent of the initial nerve/muscle disturbance.

Because the cause is unknown, no specific cure is in sight. Some speculate that certain body antibodies have attacked the nerve insulation. Perhaps a viral infection triggers that process.

GB doesn't usually recur. It is fairly common, and all ages can get it. I know of no preventive measures. And, in answer to L.Y., it is not contagious, and analysis of spinal fluid does provide evidence of the problem.

DEAR DR. DONOHUE: I need some answers. I would like to know if there is a natural diuretic for blood pressure control. I think doctors like to prescribe drugs for the money it brings. - C.C.

ANSWER: Honestly, C.C., doctors make no money from prescriptions you buy, no matter the cost.

As to a natural diuretic, I have tried to find out if there is such a thing equal in potency to prescription medicines. I can't find evidence of any such substance. There are many natural foods and drink - alcohol, caffeine, for examples - that have a diuretic effect, but I can't advise either as a kind of shortcut diuretic substitute.

Were I you, I would bite my tongue and continue with the prescription medicine my doctor gave me.

DEAR DR. DONOHUE: Thanks for explaining hepatitis C. Recently, tests showed I had B virus hepatitis, the kind commonly transmitted by contaminated needles or sexual intercourse. I have never had a transfusion, injected drugs or been sexually unfaithful. My husband now keeps me at arms' length for fear of infection. What say you about the sex situation? Could I have the C virus hepatitis? - Mrs. W.M.

ANSWER: I want to be very clear here. Blood tests are pretty reliable in distinguishing one hepatitis virus infection from another. Your test said B. That would seem to rule out the C virus.

More important is knowing which tests you had. Specific tests distinguish a current infection from harmless evidence of a long ago one. Knowing that makes a big difference. Unprotected sexual intercourse along with contaminated needles are the principal transmission routes for B virus infection. And if the disease is current, your family might need protection with the B vaccine.

I believe you when you say you have never engaged in B hepatitis risk activities. So here's another scenario. Say, first of all, that your test did show evidence only of some long ago innocent exposure. As an example, the virus can be transmitted from an infected mother to an unborn baby. In such circumstances your present liver inflammation (which is what hepatitis means generally) might be from one of many other viral or non-viral causes. Liver inflammation is not limited to the prominent viruses A, B and C. In fact, there are more than those three - D and E, for examples. And hepatitis can arise from yellow fever or mononucleosis viruses. Even chemicals can cause it - carbon tetrachloride, for example, or alcohol.

DEAR DR. DONOHUE: It is so devastating for the medical profession to insist there is no way for genital herpes to be transmitted except by sexual contact. I know two wives who have had this experience - of having the disease when the husbands do not. The other devastation is that MDs look askance and do not believe that a person is morally pure. My question: Has any research been done to find what other ways this disease can be contracted? - Mrs. E.J.M.

ANSWER: Herpes 2, the genital herpes, is usually acquired through sexual contact. Herpes 1, the cold sore virus infection, is passed from person to person mostly via saliva and oral contact.

The cold sore virus can spread to the genital area in ways unrelated to sexual activity. The fingers may have some virus on them and carry that to the genital sites. In fact, as many as 14 percent of genital infections are of the type 1 (oral) virus. But, from visual observation, the rashes seem identical.

I cannot be more unequivocal. Indeed, genital herpes can be contracted by non-sexual intercourse means. I believe the wives (or husbands) who say they got it that way. See the herpes material. Write Dr. Donohue/No.17, Box 830, Gibbstown, NJ 08027-9909, enclosing a long, stamped, self-addressed envelope and $2.

DEAR DR. DONOHUE: Can birth control pills cause a darkening of the face? - Mrs. O.O.

ANSWER: Yes. The same hormones cause this, whether in the pill or from a pregnancy. In pregnancy it is called melasma, or the mask of pregnancy. It usually leaves after pregnancy or cessation of the pill.

- Dr. Donohue welcomes reader mail but regrets that, due to the tremendous volume received daily, he is unable to answer individual letters. Readers' questions are incorporated in his column whenever possible.