DEAR DR. ROACH: What is your take on the benefits versus risks of DMSO? — W.R.

ANSWER: DMSO (dimethyl sulfoxide) has only one use approved by the Food and Drug Administration, in people with interstitial cystitis, where it is directly instilled into the bladder. It is also used (off-label, meaning without an official FDA indication) as a recovery treatment when the tube delivering some types of chemotherapy comes out of the vein.

DMSO may have a pain-relieving effect, both topically when applied, as well as in the brain, though the mechanism for this is unclear. DMSO is an antioxidant and opens pores in lipid membranes, but again it’s unclear how this relates to its possible effects on people’s symptoms.

It is an interesting and difficult-to-study compound. It is exceedingly permeable: Within five minutes of being applied to skin, it is detectable in the blood. It has a distinct flavor and odor that can be noticed after application to the skin, which makes doing a controlled trial difficult; subjects in a study find it very easy to know whether or not they have been given DMSO.

It’s estimated that people have spent billions of dollars on DMSO for other conditions, especially arthritis and inflammatory diseases. However, the evidence that it is effective is poor, largely because of the difficulty in doing good studies on this compound, but also because large-scale studies are very expensive and there is little enthusiasm on performing such studies on a cheap compound.

The risks appear to be small. Apart from the taste and smell changes, there are rare reports of allergies, discomfort in the bladder after instillation there and possible damage to the eye lens (at least in animals).

You didn’t tell me what condition you are considering DMSO for, but except in the case of interstitial cystitis (where there are other therapies more likely to be effective), given uncertain benefits, I don’t recommend DMSO despite the low risk of harm.

DEAR DR. ROACH: I know drinking a bottle of wine isn’t good for me, but is it really that bad? I’m a 74-year-old female in excellent health who stays active and enjoys relaxing with wine — before, during and after dinner. I seriously want to know if I’m really harming myself with this habit. — N.R.

ANSWER: A bottle of wine is indeed more than is recommended daily. For women, the recommendation is one glass of wine with meals. A bottle of wine contains five glasses. This amount of alcohol is thought to increase overall risk of death by about 30 percent, mostly from accidents, kidney and liver disease and congestive heart failure. There is fairly strong evidence that this much alcohol also increases risk of developing dementia. Alcohol may have a greater effect on older women, because at age 74, your liver probably does not work as well as it did when you were 20.

Put another way, your current risk of death due to the alcohol is closer to that of an 80-year-old than that of a 74-year-old, roughly speaking. Cutting down on alcohol now stops further damage and allows your body to heal itself, to some extent.

I hope I have convinced you that from your health standpoint, five glasses of wine is far too much, and I would really encourage you to stay below two glasses of wine a day.

Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.