Q: With summer just a couple of months away, I'm wondering what I can use for sunburn protection that does not contain PABA. I'm allergic to it.

A: PABA -- the most widely used sun screen agent -- can be irritating. If it irritates you, there are a few substitutes you can try.

PABA causes an allergic skin reaction in some people, especially those who are allergic to benzocaine or procaine (anesthetics), sulfa drugs (antibiotics), thiazides (diuretics) or aniline dyes. PABA may also cause trouble by staining clothing yellow.

You should be aware that PABA comes in several forms, so read labels carefully. There's PABA (or para amino benzoic acid), glyceryl PABA, padimate O (octyl dimethyl PABA) and padimate A. If you're allergic to PABA, all of these will irritate your skin. Because most sun screens contain a form of PABA, you might have to shop around or ask your pharmacist for help in finding a sun screen without it.

Sun screen agents other than PABA include benzophenones (oxybenzone and dioxybenzone), cinoxate, methoxycinnamate, and salicylates (octylsalicylate and homosalate). To cover small areas, you could also use an opaque sun screen such as zinc oxide.

One other drawback to PABA-containing sun screens is that they don't fully protect against the type of ultraviolet light that causes photosensitivity reactions. These sun-induced skin rashes occasionally occur in people taking certain medicines, such as sulfa drugs, tetracycline, phenothiazines (used to treat schizophrenia), antidepressants, thiazides and sulfonylureas (oral diabetes medications).

Q: About a year ago I had surgery to remove my gallbladder. It had several large stones. I am now experiencing the same pain that I had before the surgery. Could a gallstone be loose in my body somewhere? Surely gallbladders don't grow back!

I've also been under some stress lately. Could an ulcer be causing these symptoms? Or could the bile that used to be stored in my gallbladder be the troublemaker?

A: Between 5 and 20 percent of people who have their gallbladders removed because of gallstones either have their symptoms return or develop new ones related to the operation. There are several reasons why this might happen.

One is that the original symptoms were not actually due to gallstones in the first place. Both gallstones and various abdominal symptoms occur fairly frequently. So when your doctor checks your gallbladder as a possible cause of abdominal pain, yellow jaundice, indigestion or other symptom, there's a reasonable chance that gallstones will show up, even though they're not really at fault. In these cases, your symptoms will probably continue after you have your gallstones taken out, and you'll need to have your problem looked into further. It's interesting that you're wondering about a possible ulcer, because ulcers are one of the conditions that can mimic the symptoms of gallbladder disease.

Another cause of continuing symptoms after gallbladder surgery is having one or more gallstones still present. During the operation, surgeons routinely check for any stones that may have escaped from the gallbladder into the bile duct, the tube connecting the gallbladder to the intestines. But up to 5 percent of people have a small stone left behind, which may cause a painful blockage in the bile duct or other problem. A gallbladder scan -- which takes a picture of the bile ducts -- will usually show if you still have a stone inside. If so, it may be possible to remove it without surgery through a tube inserted through the mouth and passed to the opening of the bile duct in the small intestine.

Other possibilities are that you've developed some complication from your gallstones or your operation that's causing your symptoms to return, or you have a new condition that just happens to cause similar symptoms. In any event, you'll need these different possibilities sorted out.

Although many people think of bile juice as being toxic, it's a fairly harmless digestive fluid that in itself wouldn't be causing your symptoms. Bile juice is made in the liver, stored in the gallbladder and released into the intestines to help digest foods. In case you wonder whether not having a gallbladder is the source of your problem, people usually do well without one.

Q: My husband is allergic to penicillin and has a physical disorder that could be potentially life threatening if treated improperly. I would like him to get a medical I.D. of some kind: card, bracelet, dog tag, whatever. My question is, do emergency medical personnel look for these things? Would it be worthwhile for him to have a medical I.D.?

A: I think identification bracelets that warn of special medical conditions are worthwhile, and I frequently recommend them to my patients.

Emergency and health care personnel are trained to look for these bracelets in the event of an accident or emergency. I made a brief survey of some local emergency room nurses and emergency medical technicians; all supported use of the bracelets and said they've found them helpful in life-threatening situations.

Medic Alert is the brand name of a metal emblem that can be worn as a necklace or bracelet. It will alert health professionals to special medical conditions, such as medication allergies, diabetes, epilepsy and other disorders that may cause unconsciousness and prevent you from speaking for yourself. It will serve the same purpose if you're rendered unconscious in an accident.

For more information or to order a Medic Alert bracelet, write Medic Alert, P.O. Box 1009, Turlock, Calif., 95381, or call 800-344-3226. The cost for one bracelet is $20 and includes a lifetime membership in Medic Alert, which provides 24-hour-a-day telephone access to your personal emergency medical information.