A fix for a dry cough: whenever I'm in climate-controlled buildings or extreme temperatures, my airways get irritated and I have dry coughing fits. Allergy tests turned up negative. What can I do? - ask the experts: answers to your questions from the leaders in natural medicine

ADRIANE FUGH-BERMAN, M.D., REPLIES: While I wouldn't expect that antioxidants, astragalus, or milk thistle would interfere with tamoxifen, no studies have been done on possible interactions. Consuming antioxidants in food is associated with a lower risk of cancer, but antioxidants in pill form have had mixed results and may be most effective for preventing cancer in those who are nutritionally deficient. Neither astragalus, which is said to stimulate the immune system, or milk thistle, which may help protect the liver from toxins, has been tested for preventing breast cancer or cancer recurrence in humans.

Whether herbs or antioxidant vitamins should be used during chemotherapy or radiation is a controversial subject, and I have mixed feelings on it. Because radiation and some chemotherapy treatments attack cancer cells by oxidizing them, some physicians think that taking antioxidants reduces these treatments' effectiveness.

Other physicians say that using antioxidants and herbs during conventional treatment helps protect normal cells and minimizes side effects. Theoretically, that's not necessarily a good thing; the reason side effects decrease may be that antioxidants are interfering with the treatment. We are probably not going to answer this question anytime soon; it's a difficult research project to pursue.

I think that the safest thing to do is to avoid vitamins and herbs while undergoing chemotherapy or radiation. After treatment is over, though, it's probably okay to take vitamins and the herbs that you mention while you're taking tamoxifen.

Eat Your Calcium

I eat unhulled sesame seeds daily for their calcium content, but I notice that I pass many of them in my stools. Does this mean I'm not getting the calcium benefit?

CAROLYN DEAN, M.D., N.D., REPLIES: To make the calcium in sesame seeds digestible, you need to break open the hulls with a coffee grinder. Chewing the seeds will work, too, but you're bound to swallow many of them whole.

You're smart to get your daily requirement of calcium from food since this form is more digestible than supplements. (Men and women ages 19 to 50 should get 1,000 mg daily. Adults age 51 and older should aim for 1,200 mg.) Sesame seeds aren't a bad source, but you'd have to eat 2 tablespoons to get just 175 mg of calcium. Cooked leafy greens like kale, collards, dandelion, and beet tops have 100 to 225 mg per cup. Sardines have nearly double that amount: 351 mg in seven sardines. Even though dairy products tend to be higher in calcium than seeds and greens, some scientists believe that the animal fat in them inhibits their digestion.

If you decide to take calcium supplements, look for lactates, citrates, and amino acid chelates, preferably in capsule form rather than hard tablets because they're more easily broken down. In my clinical experience, these forms are most readily absorbed by your body.

Meet the Experts

Robert Anderson, M.D., is a semiretired family doctor and president of the American Board of Holistic Medicine. He is an advisor for the medical journal Alternative Therapies in Health and Medicine and author of A Clinician's Guide to Holistic Medicine (McGraw-Hill, 2000).