Bloody noses are very common in winter due in large part, as you suggest, to seasonal dry air that irritates and dries nasal membranes. Colds, which are also more frequent in winter, irritate these membranes as well. Other common causes of nosebleeds are repeated nose blowing, allergies, and some common drugs that dry the nasal membranes, including antihistamines and decongestants used to control a runny or stuffy nose. Smoking also contributes to nasal dryness and irritation, so if you smoke, quit.

Most nosebleeds (more than 90 percent) come from small blood vessels (capillaries) located in the front of the nose, usually in the septum, the divider between your nostrils. Some people are more at risk of nosebleeds because their capillaries are closer to the surface. Occasionally, nosebleeds can be a symptom of a more serious systemic problem, such as high blood pressure or a clotting disorder.

One way to deal with the dry air that contributes to your nosebleeds is to buy a humidifier for your home. You also could try a product called Ayr, a saline nasal gel sold in drug stores; just squirt a little in your nose. Other options are to rub some Vaseline, liquid vitamin E, or aloe gel in your nose. You can also take vitamin C, which decreases the fragility of small blood vessels. The dose is 200 milligrams twice a day. Yet another possibility is grape seed extract or a proprietary pine-bark extract called Pycnogenol; these are sources of anthocyanin pigments that have the same effect. All are worth a try.

To deal with active nosebleeds, sit upright or lean your head slightly forward and pinch both nostrils (do not lean back). Hold your nostrils shut for five to 10 minutes without letting go and breathe through your mouth. By plugging your nose, you stop the blood flow and allow a clot to form. If the bleeding hasn't stopped after 10 minutes, spray some decongestant into your nose. This shrinks the blood vessels. Then hold your nose again for 10 minutes. You could also try sniffing a little bit of powdered yarrow (Achillea millefolium), a safe herbal remedy that stops surface bleeding.

If after 20 minutes you're still bleeding, see a doctor. You may need to have the blood vessels cauterized with silver nitrate solution. You'll also likely need professional help if you're taking blood thinners or large amounts of aspirin. Note that high doses of vitamin E and fish oil have blood-thinning effects that can contribute to the problem.

Andrew Weil, M.D.

The warning you see on your CD probably applies to binaural beat therapy. Binaural beats are different sound signals delivered to each ear via headphones. Your brain meshes the two sounds into a single tone. This effect was discovered in 1839 by Heinrich Wilhelm Dove, a Prussian physicist and meteorologist who coined the term "binaural beats."

Over the years binaural beat therapy has been used to study hearing and sleep cycles, to treat anxiety, to induce various brain wave states and to promote relaxation and sleep. (Monaural beats are already combined and don't require headphone use.)

Most people have no trouble with binaural beat therapy. However, there's at least a theoretical chance of running into trouble if you have epilepsy or an irregular heartbeat (especially if you have a pacemaker).

I discussed this interesting issue with Joshua Leeds, a sound researcher and the music producer I worked with on my CD Sound Body, Sound Mind: Music for Healing, which features music designed to influence brain wave activity and encourage the body's natural potential for healing. Mr. Leeds says that he has been told that in very rare instances someone with a tendency toward seizures could trigger an episode while listening to binary beats. However, he tells me that in the 25 years he has worked in the field, he has never heard of a single case of that sort. Still, most practitioners caution individuals with seizure disorders to check with their doctors before trying binaural therapy.

As for cardiac issues, the concern is that, just as brainwave patterns are altered by binary beats, heart rhythm may be affected as well.

Labels on some binaural beat therapy products also warn against operating complex machinery while listening. This is because the relaxation induced isn't compatible with driving or using other machines that require your full attention. Joshua Leeds tells me that the standard disclaimer on some of his products also contains this language: "In the unlikely event that you experience any unusual physical or mental discomfort, immediately discontinue use." ;

Adverse events when using binaural beat therapy appear to be extremely rare, but in our litigious times, it's not surprising that manufacturers seek to protect themselves with such warnings. If you don't have epilepsy or heart problems there's probably no need for you to formally consult your physician before playing it, and please don't drive while listening to your sleep therapy CD.

Andrew Weil, M.D.

ALS (amyotrophic lateral sclerosis) is also known as Lou Gehrig's disease, after the legendary New York Yankees' star of the 1920s and 1930s; he was diagnosed with the disease in 1939 and died of it in 1941. ALS causes degeneration of nerve cells in the brain and spinal cord that control voluntary muscle movement.

As nerve cells waste away or die, they no longer can send messages to muscles, which in turn leads to muscle weakening and eventually to the inability to move the arms, legs and body or to swallow. When chest muscles stop working, patients become unable to breathe on their own. ALS doesn't affect the senses or thinking ability and only rarely affects bladder or bowel function.

The cause of most cases of ALS is unknown, but about 10 percent are familial, associated with a genetic defect. Toxic injury to the brain may start the degenerative process in nonfamilial ALS.

Creatine, an important compound in muscle tissue, is the building block for ATP (adenosine triphosphate), the energy storing compound that fuels muscles during short, high-intensity exercise such as weight training.

I discussed your question about its use in ALS treatment with David Perlmutter, M.D., a neurologist in Florida (see www.perlhealth.com). He says that creatine, taken by itself, has been studied and found ineffective in the treatment of ALS. However, he tells me that a new study underway at the Massachusetts General Hospital is looking at creatine in combination two different doses of the breast cancer drug Tamoxifen to see if they are safe and effective for use in ALS patients. Dr. Perlmutter and his associates have been using Tamoxifen in their ALS patients for the past three years along with a ketogenic diet, which is very high in fat and very low in carbohydrates. The diet keeps the body in a constant state of "ketosis," in which it is forced to burn fats only. Dr. Perlmutter says the diet has been found to be exceptionally effective in the experimental animal model of ALS. ;

Tamoxifen emerged as a possible treatment for ALS more than 10 years ago when a neurology professor at the University of Wisconsin Hospital and Clinics in Madison saw that one of his ALS patients who was taking Tamoxifen for breast cancer seemed to be improving neurologically; the drug seemed to be slowing the progression of her ALS. Studies since then have shown that Tamoxifen prolongs survival in ALS patients with few side effects (primarily hot flashes). Since then preliminary evidence from animal studies of stroke and oxygen deprivation also suggests that Tamoxifen is neuroprotective.

As for Rilutek (riluzole), Dr. Perlmutter says that while this drug has been FDA approved for treatment of ALS, it has little effect on disease progression and is often associated with serious side effects.

Andrew Weil, M.D.

Vibration machines have become fixtures in gyms, and some studies indicate that they may have specific benefits in certain sports. They are also being heavily promoted as a way to strengthen bones, but so far, at least some of the research hasn't supported the claims.

A study from the University of Toronto published in the Nov. 15, 2011 issue of the Annals of Internal Medicine tested vibration machines for a year and found no differences in bone density in the 202 postmenopausal women who participated. At the outset, the women's bone mass was low but not low enough to require drug treatment. Their bone density was measured when the study began and a year later when it ended.

The researchers randomly divided the women into three groups; two groups were assigned to stand on a whole body vibration platform that moved at one of two speeds for 20 minutes a day. The third group served as controls. For the duration of the study all the women took calcium and vitamin D to see if the supplements plus vibration reduced the rate of bone loss.

Results showed no statistically significant difference in rate of bone loss over the year among the women in the vibration groups compared to the controls. The researchers concluded that whole body vibration should not be recommended to prevent bone loss.

The best way to avoid the age-related loss of bone mineral density that leads to osteopenia (bone mass that is low but not low enough to be classed as osteoporosis) and then to osteoporosis is to build up sufficient bone mass early in life. Maximum bone mass is reached around age 35. Once you reach midlife, your best strategy is strength training, also called resistance exercise.

Bone is constantly being re-formed by the action of opposing forces, some destructive, some constructive, in response to the stresses and demands placed on it. These changes are under precise cellular and hormonal control and can take place very quickly. Resistance exercise places demands on bone that cause the constructive influences to dominate, halting loss of mineral density and even adding to it. (Some aerobic activities such as walking, climbing stairs, and jogging help to maintain bone density, but others such as swimming and cycling do not.)

Bear in mind that a sedentary lifestyle promotes bone loss as well as muscle loss. Conversely, muscle use promotes the building of bone. Regular physical activity strengthens both muscles and bones, slows bone loss and decreases the risk of injury from falls. As the Toronto vibration study indicates, there is no substitute for the physical activity needed to keep your bones strong.

Andrew Weil, M.D.

We need potassium for the proper functioning of many major organ systems - it is essential for the heart, kidneys, muscles, nerves, and digestive system to operate normally. Potassium is also required for regulating fluid balance, the body's acid-base balance, and blood pressure. In addition, considerable scientific evidence suggests that a diet providing at least 4.7 grams of potassium daily lowers the risk of stroke, high blood pressure, osteoporosis and kidney stones and that a diet rich in fruits and vegetables, which are among the best sources of potassium, is associated with a reduced risk of cardiovascular disease.

Despite its importance to optimum health, I do not recommend that anyone take potassium supplements unless a doctor has prescribed them. We all can get adequate potassium from food sources, and for that reason supplements are needed only under specific medical circumstances. Potassium deficiency is rare, and when it occurs, it usually affects people with kidney disease, gastrointestinal disease and those who take diuretics.

Although bananas are probably the best known source of dietary potassium, other particularly good ones are baked potato with skin, prune juice, prunes, raisins, tomato juice and tomatoes, almonds, sunflower seeds, spinach and artichokes. Meat, fish and chicken are also good sources as are soy foods.

Taking potassium supplements on your own can lead to hyperkalemia, a higher than normal level of potassium in the blood that can be life-threatening and requires immediate medical treatment. The most common cause of hyperkalemia is acute or chronic kidney failure, but it also can be a side effect of certain medications, including angiotensin-converting enzyme (ACE) inhibitors (for lowering high blood pressure), non-steroidal anti-inflammatory drugs, and blood thinning agents such as heparin. Hyperkalemia can also stem from alcoholism or type-1 diabetes as well as excessive use of potassium supplements. Symptoms include muscle fatigue, weakness, paralysis, abnormal heart rhythms and nausea.

Symptoms of potassium deficiency, called hypokalemia, include irregular heartbeat, muscle weakness and cramps, and mood changes, as well as nausea and vomiting. A severe deficiency can lead to muscle paralysis and abnormal heart rhythms that can be fatal. Deficiencies usually stem from a loss of potassium due to prolonged vomiting, the use of some diuretics and some types of kidney disease. It is highly unlikely that a low dietary intake of potassium, by itself, would ever lead to a deficiency.

Andrew Weil, M.D.