Dear Dr. Donohue: I am a woman of 67 and was diagnosed as having a hiatal hernia three years ago. I am in pain every day. Can you fill me in on what to expect and what can be done about it?

- W.C.

Answer: Hiatal hernias are bulges of the stomach upward into the chest. The bulge occurs at the site where the swallowing tube - the esophagus - passes through the diaphragm muscle to join the stomach.

The pain you have comes from a regurgitation of stomach acid into the esophagus. Quite often acid regurgitation occurs without a hernia. So the spotlight should not shine so much on the hernia as it should on the reflux of acid from stomach to esophagus.

A program to combat the splashing of acid into the esophagus effectively eliminates pain.

Don't smoke.

Avoid fatty foods.

Don't drink coffee, even decaffeinated coffee.

Stay arm's length away from chocolates, peppermints, alcohol, orange juice and tomato juice.

Elevate the head of your bed by putting 6-inch blocks under the bedpost. That way, gravity can help keep stomach acid out of the esophagus while you sleep.

Two tablespoons of antacids taken one and three hours after eating and again before retiring can neutralize stomach acid.

Cimetidine, ranitidine or famotidine can decrease the production of stomach acid and quell heartburn pain, which is what you have. They are available without a prescription.

If you're not making any progress with self-treatment, your doctor can prescribe medicines that are almost 100 percent effective in relieving pain.

I'm sending you my "Hiatal Hernia, Heartburn and Acid Reflux" pamphlet, which provides details about your common and painful condition. Readers can order a copy by writing: Dr. Donohue - No. 18, Box 5539, Riverton, NJ 08077-5539. Enclose $3 and a self-addressed, stamped (55 cents) No. 10 envelope.

Dear Dr. Donohue: Doctors now agree that most stomach and duodenal ulcers are caused by the Helicobacter pylori bacteria and that they can be treated successfully with antibiotics.

Since hiatal hernias are in part related to excess acid, could this be good news for sufferers of that disorder?

- M.P.

Answer: That's a good thought, but the heartburn of hiatal hernia comes from stomach acid in the esophagus. The H. pylori bacterium seems not to be implicated in heartburn pain. Stomach acid reflux is the culprit.

Doctors attack hiatal hernia pain by trying to reduce stomach acid and stop its splashing into the esophagus.

The Helicobacter germ causes ulcers by boring holes in the protective covering of the stomach and duodenum, allowing stomach acid a free access to the tissues that lie beneath that protective coat.

The esophagus has no such covering. Therefore, Helicobacter is not likely to be involved in heartburn pain.

Dear Dr. Donohue: My platelet count was 40,000. I had no symptoms but I was given intravenous gamma globulin, which brought the count up to 190,000.

Then the count dropped again. Another treatment of gamma globulin brought it back to normal.

My doctor says if the count drops again, I will have to have my spleen removed. Why?

- J.W.

Answer: Platelets, also called "thrombocytes," are small blood cells essential for clot formation. The normal count is 150,000 to 400,000.

When the count drops to the 50,000 range, bruises from even minor bumps appear on the skin. With counts lower than 20,000, spontaneous bleeding can occur.

The spleen gobbles up platelets when the immune system turns against them. Gamma globulin blunts the spleen's appetite for platelets. So do cortisone drugs.

If drugs fail, then spleen removal can correct the situation.

Dear Dr. Donohue: Will you please give me some information on jaundice? I have been told I have it. I am scheduled for a liver ultra-sound.

- G.D.

Answer: Jaundice isn't a disease. It's a symptom that points to the liver as the source of trouble.

With jaundice, the skin yellows, as do the whites of the eyes. The yellow color is bilirubin, a pigment coming from worn-out red blood cells.

A healthy liver clears the blood of bilirubin. A liver that is not up to snuff allows pigment buildup in the blood and eventually into the skin and eyes.

The yellow discoloration is not harmful. But it's a beacon to look for liver disease.

A stone blocking the drainage of bile from the liver can cause jaundice. So can liver infections, hepatitis. The list of possibilities is quite long.

The ultrasound of your liver can help detect what has gone amiss.