Common sense measures alone will often keep hemorrhoids at bay. Maintaining normal weight, regular exercise, drinking plenty of nonalcoholic fluids to prevent constipation, avoiding laxatives and prolonged standing or sitting all help. And so does a balanced diet containing fiber.

Americans spend more than $100 million a year on nonprescription remedies for hemorrhoids, more than $60 million of it on a single product, Preparation H. Although the Food and Drug Administration has yet to act on its findings, the agency's Advisory Review Panel on Over-the-Counter Hemorrhoidal products reported in 1980 that virtually all the multi-ingredient products were questionable on grounds of safety, effectivness or both.

Sometimes it's a matter of quantity, rather than quality. Among the ingredients of Preparation H, for example, is shark liver oil, which the panel found to be a safe and effective protectant for irritated hemorrhoidal tissue. However, the panel also found that in order to be protective, 50 percent of each ounce of the product would have to be shark liver oil, instead of the 3 percent in the Preparation H formula. Nor did the panel find evidence that shark liver oil was any better a protectant than zinc oxide or petroleum jelly, which cost less, especially when purchased alone.

Petroleum jelly and zinc-oxide paste or powder are time-tested remedies for the temporary relief of external hemorrhoids because they protect irritated tissues, allowing them to heal. And both external and internal hemorrhoids often respond to an ice bag on the anus, stool softeners such as Metamucil and bed rest.

Moist heat can be very soothing, too. Many doctors, for example, advocate sitting in very warm (110-115 degrees F) water for 15 minutes two or three times a day, but be sure the water is not so hot that it is painful to your hand. Warm damp towels also can be used.

If at all possible, avoid straining when moving your bowels. The pressure it puts on hemorrhoidal veins inititally compresses them, but ultimately stretches their walls. In fact, the increased pressure exerted on the pelvis by pregnancy is a frequent cause of hemorrhoids at that time.

Be sure, too, to keep the anal area clean, especially after bowel movements. But go easy on rubbing or wiping. Instead, use moistened toilet paper to blot or pat the irritated tissue and use warm water and a mild, unperfumed soap.

Cleansing is particularly important before applying any cream or ointment to hemorrhoidal tissue. Otherwise, harmful bacteria may be trapped underneath. And you may well be more comfortable if you select a porous fabric like cotton for your underwear.

Finally, piles that do not begin to respond to self-care measures within a week should be seen by a doctor. Remember, too, that although rectal bleeding is not necessarily a sign of colon cancer, there is always that possiblity, so it should always be evaluated medically and never ignored.