Colic is quite common, but no one knows exactly what it is. The medical definition is crying in a healthy, normally developing baby, which seems unrelated to pain or hunger, and which occurs most days or evenings over a period of time.

Typically, colic starts in the first month, and goes on until your baby is three months or so.

It's not known why some babies are affected more than others, or why it sometimes suddenly disappears. It could be to do with immaturity of the gut, and as the baby's digestion matures, they become more able to tolerate the sensations of digestion. Alternatively, it may be bubbles of trapped wind, causing discomfort.

The baby is unable to be comforted It occurs in babies under four months of age It's usually worse in the evening after feeding and is often highlighted by high-pitched screaming

Massage - apply gentle pressure on the tummy by, for example, holding your baby across the crook of your arm or face down over your knees, or upright over your shoulder and rubbing your baby's back and/or tummy.

Diet - if breastfeeding, think about your diet to see whether particular foods you eat seem to make your baby's colic worse. It's unusual for this to be the case, but it's worth thinking about, even so.

Teats - if bottlefeeding, try anti-colic teats. Formula - if formula feeding ask your health visitor about different brands, including formula for unsettled, hungry or lactose-intolerant babies

Sucking - offer your baby a chance to suck on breast, bottle or dummy as this can be comforting.

Medication - always check with your doctor, pharmacist or health visitor before giving your baby any medications. Various over-the-counter preparations may help, such as herbal drinks, homeopathic drops, gripe water and baby colic medications. 'Colic dance' - while hugging your baby (some prefer to be held slightly away from your body to have eye contact) gently sway with your knees bent, alternating back and forward, side to side and up and down. Some babies like a low humming sound at the same time.

If your baby is 'colicy' in the evenings, make sure lunch is your main meal of the day and your main source of protein and energy. You'll need to keep your strength up.

Many parents find the stress of a 'colicy' baby becomes too much. Ensure you have support and are able to take a break. Try to share the crying times. You could also ask your health visitor if there are any local support groups for parents of crying babies.

If your baby's crying ever becomes more than you feel you can stand, pass the baby to someone else, or if you're alone, put him down safely in a cot or pram and go into another room where you can't hear the crying, so you can calm down before trying again.