According to new research babies who are put to bed with a dummy in their mouths have a significantly lower risk of cot death.
It appears the benefits are greatest among babies who are considered to be at highest risk of sudden infant death syndrome (SIDS), such as those whose mothers smoke or share a bed with them.
Experts are now saying parents should be encouraging the use of dummies for babies, but some campaign groups urge caution.
Statistics show that more than 300 babies, mostly under 12 months old, die every year from cot death in the UK, and it remains the most common cause of infant mortality.
The study provides insight into the protective effect of dummy use.
Experts say the death toll has fallen steeply since parents were advised to always put babies to bed on their backs, but there is still much confusion around the causes of cot death and the best ways of preventing it.
Researchers from the Kaiser Permanente research foundation in California interviewed the mothers of 185 babies who had died of SIDS, and compared their experiences with 312 "control" parents whose children were healthy.
They found that when all other risk factors, such as age of the mother, socio-economic status and smoking habits were taken into account, babies who slept with dummies were 90 percent less likely to be victims of cot death.
The researchers say the reduced risk was strongest when the babies were in what they called "adverse sleep environments", which are already known to increase the dangers of cot death, such as sleeping on their stomachs, or in the same bed as their parents or with mothers who smoked.
The experts believe that dummies may help to prevent cot deaths by changing the configuration of the airway passage surrounding the nose and mouth in a way that can stop babies from accidentally suffocating in their sleep.
It is also thought that sucking on a dummy may also help to boost development of the upper airways.
Dr De-Kun Li, senior research scientist at the foundation and author of the study, says the use of a dummy seems to reduce the risk of SIDS and possibly reduces the influence of known risk factors in the sleep environment.
While the number of UK cot deaths has fallen by 75 percent since a high-profile government awareness campaign was launched in 1991, the children of young, single mothers and those from poorer families have a much greater chance of falling victim to the syndrome.
Li said dummy use among higher-risk babies was comparable with those in the low risk groups in his study.
He concludes that advocating the use of dummies for infants in high-risk populations may have the potential to further reduce the incidence of SIDS.
However, despite the wealth of research surrounding cot deaths, many parents are still unsure about the best ways of preventing it.
A recent survey by the Foundation for the Study of Infant Deaths (FSID) found that a third of new parents had not received any information about prevention methods.
A spokesperson for the FSID says the current study is very interesting and appears to be convincing that the use of a dummy reduces the risk of cot death, but the statistical analysis is very complicated and needs careful study.
The study is published in the current edition of the British Medical Journal.