Q. My elderly mother lives at home with us. She has Alzheimer's disease, and her unpredictable behavior and angry outbursts are very upsetting to us. Her doctor says there is no cure for her condition. Is there anything that can be done?

A. Alzheimer's disease is the most common cause of senility, a gradual failing of mental function. Contrary to what many people think, senility is not an inevitable part of aging. In fact, only about 5 percent of people over 65 will suffer from this condition. Alzheimer's disease can be mild or severe, and affected people can be relatively easy to deal with or frustratingly difficult.

Since most people with Alzheimer's disease are cared for by their families, it's especially important for their care-givers to take advantage of the many supportive services available. I highly recommend the book "The 36 Hour Day" by Drs. Nancy Mace and Peter Rabins, two Johns Hopkins health workers who specialize in helping families care for people with senility. The book is written as much for family members as for the person afflicted with senility. It contains extremely practical, down-to-earth advice on how to compassionately care for and cope with persons with this devastating disease. Chapters discuss specific ways of dealing with unpredictable behavior and angry outbursts. It's available at many local bookstores in paperback.

An organization you should know about is the Alzheimer's Disease and Related Disorders Association (ADRDA). The two local chapters are located in Bethesda at 7979 Old Georgetown Rd., Suite 100, Bethesda, Md. 20814 (652-6446) and in Falls Church at 200 E. Broad St., Apt. 1, Falls Church, Va. 22046 (534-8446). This self-help organization provides support in the form of newsletters, literature and conferences for people and families faced with senility. Support groups meet regularly to share feelings and discuss ways of coping with this cruel affliction.

Q. My doctor advises bunion surgery for my continually aching feet. I'm 40 years old and have been bothered increasingly in the last 10 years even though I've stopped wearing high heels in favor of sensible shoes. But surgery scares me. What are my alternatives?

A. A bunion is a bony deformity at the base of the first toe. It is also known as hallux valgus. If you have foot pain only while wearing shoes, you may respond to conservative measures such as using a special shield prescribed by a podiatrist or orthopedic surgeon to protect the bunion from pressure. Wearing wider shoes also may help.

However, if your foot hurts with movement of the first toe, you probably have a problem in the first toe joint. If this is the case, conservative treatment will probably fail, and surgery is called for.

The decision for surgery is best dictated by the type of deformity and amount of pain you're having. Hallux valgus surgery is relatively minor, safe and effective. If your feet have been continually aching for 10 years, it's certainly worth considering.

There are many types of surgery, and most involve cutting out the bony prominence as well as surgically correcting the underlying malalignment of the first metatarsal bone, which extends behind the first toe.

Another kind of surgery, called minimal incision technique, is not for everyone. Simply removing the bony bump is not sufficient in most cases, because it does not always correct the underlying structural deformity and malalignment of the first metatarsal bone. In such cases, the deformity and pain, which are really manifestations of this underlying structural abnormality, will recur.

The type of surgery chosen depends on the X-ray appearance and physical examination of the feet and the preference of the podiatrist or surgeon.

Q. What can I do for bad breath?

A. You can treat most causes of bad breath by practicing good oral hygiene.

Bad breath can result from problems in the mouth, especially cavities and inflammation of the gums (gingivitis or pyorrhea) or from things put into the mouth, such as cigarette smoke, alcoholic beverages, onions and garlic. In most cases, brushing after meals will remove food particles that may impart an odor to the breath if they remain in the mouth.

Onions and garlic are unusual in that the substances responsible for their strong scent are absorbed in the bloodstream and later released into the lungs, where they are exhaled. So no amount of brushing will eliminate their odor until it fades by itself, usually within 24 hours.

Sometimes not eating for many hours will make the breath a little strong, so eating regularly may also help.

Rarely, bad breath is caused by a disease outside the mouth. These include chronic sinus or lung infections, untreated liver or kidney failure, stomach disorders, and tumors or infections in areas adjacent to the mouth. These conditions are usually evident by the other symptoms they cause.

Good oral hygiene means regular brushing, professional teeth cleaning once or twice a year, and daily flossing. If your gums bleed with brushing or flossing, it's a good bet you have gingivitis and would benefit from professional cleaning and regular flossing.

The character of the breath changes with aging. Children, for instance, rarely have bad breath without an obvious cause -- usually a bad cavity. If the above measures aren't fully effective for you, try sugarless breath mints or mouthwashes.