Q:. I have a bad case of acne, and none of the products I've bought at the drug store do any good. What else can I try?

A :Acne is such a common skin disease it is often considered harmless. But since your acne can cause unsightly and permanent facial scarring, it's worth taking seriously and treating vigorously.

Contrary to what we used to think, foods such as chocolate, french fries and ice cream seem to have little effect on acne. If you feel that a certain food consistently causes acne flareups, you can avoid it, but I'd caution you not to restrict your diet unnecessarily.

Squeezing pimples can drive the acne inflammation deeper into the skin and make matters worse.

Probably the most effective products you can buy without a prescription are those containing benzoyl peroxide, usually in concentrations of 5 and 10 percent. Benzoyl peroxide causes the skin to be dry and peel, and may be irritating, so use it carefully at first. Your doctor or pharmacist will recommend a few brands to try. If you have mild acne, benzoyl peroxide usually helps, but with severe acne you'll probably need prescription medications.

Severe acne is, in part, a skin infection, so antibiotics are commonly used to treat it. Antibiotics for acne come in two forms -- pills, and lotions you apply to affected skin. Acne is caused by plugging and inflammation of oil glands, and another medicine acts to combat this. Topical retinoic acid, a derivative of vitamin A, increases the growth of new skin and keeps skin glands and pores from becoming plugged. Retinoic acid (brand name Retin-A) is irritating, and you should use it with a doctor's supervision.

You may have heard about a new oral form of retinoic acid, called Accutane, which has helped victims of severe acne remarkably. But this medicine is potentially toxic and has caused serious birth defects. You should only use this with strict medical supervision, and, if a woman, you absolutely should not become pregnant while taking it. Many physicians won't prescribe it unless you're taking birth control pills or have an IUD.

Q: My pulse is normally slow, about 54 beats a minute, and health care professionals always appear concerned about this. I've read that aerobic exercise results in a slow pulse rate, but I don't exercise regularly. Why is a slow pulse okay if achieved by exercise and a cause for concern if it occurs naturally?

A: Medical textbooks usually say the normal range of the pulse is between 60 and 100 beats a minute, with 72 being the "average." But many people who are perfectly normal have pulses below 60.

Studies in normal people have shown a wide range of pulse rates, from as low as 40 to as high as 120. The reason that health care professionals might have appeared concerned is that some heart disorders can cause a slow pulse.

An electrocardiogram will identify most cases of an abnormal heart rhythm. If you've had one done and it was okay, you probably don't need to have it repeated unless something new develops.

Your doctor may also have you exercise and then measure your pulse to see if it increases as expected. Some people are born with a heart disorder in which the pulse doesn't increase in response to activity as it should.

The most important factor in deciding whether a heart rate is abnormally slow is the presence of symptoms. If you do perfectly fine with a "slow" pulse, you probably have nothing to worry about. But if you have shortness of breath with exercise, chest pain or fainting, it may be related to a too-slow heart rate.

Q: I'm in my late thirties, have fibrocystic breast disease and have had one breast biopsy, which was benign. The biopsy was done because of a suspicious lump found on a mammogram. How often should I continue to have mammography?

A: Having fibrocystic breast disease and a benign biopsy makes you, at most, only minimally more likely to develop breast cancer. The main issue behind your question rests on the use of mammography as a screening tool for the early detection of breast cancer.

After years of extensive study, the American Cancer Society currently recommends the following schedule of mammography -- essentially, a breast X-ray -- for women with normal breasts: between 35 and 40, get an initial or "baseline" mammogram. Between 40 and 50, have a mammogram every one to two years. After 50, have one every year.

Women who have an abnormality in their breast, a strong family history of breast cancer, or other factors that make them more likely to develop breast cancer should have mammography earlier or more frequently or both, as determined by their doctor. Moreover, mammography should supplement, and not substitute for, monthly breast self-examination and regular breast exams by a physician.

For a number of reasons, many physicians and patients have not followed the ACS recommendations. Initially, there was a concern that the radiation of mammography might actually cause some breast cancers, but with the newer instruments in use today, which deliver less than one "rad" of radiation exposure to both breasts, the benefit of mammography, as measured by potential lives saved, outweighs the risk.

Other obstacles to the adoption of these recommendations include the cost of mammography, patient anxiety, necessity of biopsying some benign breasts in order to find those with early cancer, and attitudes of patients and physicians regarding this procedure.

It's clear, however, that early detection and treatment are important in fighting breast cancer, which affects one woman in 11. So I support the guidelines of the American Cancer Society. Unless your biopsy showed a precancerous condition, I'd recommend the schedule of mammography outlined above.