Although colic is one of the most common infant conditions  -- according to some experts, up to one-third of all babies suffer from it  -- it is perhaps the one we know the least about. Doctors have been debating for years over its causes and cures. Here's what most have agreed upon: Colic usually begins when a baby is about three weeks of age and disappears around two to three months later. Its most apparent symptom is a period of intense crying that lasts for longer than three straight hours, most commonly in the late afternoon or evening. Sometimes a colicky baby will clench his fists, become red in the face, or pass gas while he cries. Although the child seems to be in pain, most experts say that colic is much more difficult for the parents than it is for the baby.

There is no one cure for colic, but here are some remedies to try:

• Swaddling is a good place to start. One theory is that babies who have colic are more sensitive than others and are therefore overstimulated by their environment, and swaddling can help them feel more comfortable. Make life as soothing and predictable as you can for your easily stressed child  -- stick to a nighttime routine and keep your household-noise level low.

• Some researchers believe that colic is the result of an immature digestive system. Try a bottle that is designed to minimize air bubbles and prevent gas. A predigested soy formula, such as Nutramagen or Carnation Good Start, may be easier on Baby's tummy. Over-the-counter anti-gas drops that contain simethicone are also recommended by some doctors, but be sure to talk to yours before going this route.

• Your breastfeeding baby may be allergic to certain foods in your diet, such as milk products, cauliflower, broccoli, cabbage, eggs, chocolate, and caffeinated beverages. Consult with your doctor.

• Motion is often an excellent colic soother: Put your child in an infant swing, strap her in the car seat and place her on a running clothes dryer (always hold on to the car seat so it won't fall off), or put her in an infant carrier and walk around the house. You can also try taking Baby for a drive  -- the car sounds themselves may also help.

• "White noise" may work because it blocks out other types of stimulation. Turn on the vacuum cleaner, tune your radio to static, or make a tape of a combination of these noises.