E-cigarettes that were launched to let people to kick the tobacco habit have left many parents worried.

Adults are concerned that the use of e-cigarettes by children and teens would later encourage them to use tobacco products.

A poll on children's health by the University of Michigan's Mott Children's Hospital raises the alarm that parents are concerned about their children trying e-cigarettes, which are battery-operated devices that look like cigarettes but don't burn tobacco.

E-cigarettes have replaceable cartridges of liquid containing nicotine, which is inhaled as a vapour along with flavours like chocolate, fruit, candy or even tobacco.

"This poll shows high levels of concern about e-cigarettes and the possibility that kids who try them could start smoking tobacco," said Matthew M. Davis, director, National Poll on Children's Health.

Advocates of e-cigarettes say they are a healthier alternative to tobacco smoking and argue it may help smokers to quit.

In the poll, 86 percent of adults said they have heard of e-cigarettes, while only 13 percent have ever tried one. Among parents, 48 percent said they are very or somewhat concerned that their children will try e-cigarettes.

Meanwhile, 65 percent of adults think e-cigarettes should have health warnings like tobacco cigarettes and other nicotine products.

"E-cigarettes are a relatively new product, with little information about safety or long-term health effects. However, the public is clearly aware of the devices and concerned about their impact, according to this poll results," said Davis, professor of pediatrics and internal medicine at the U-M Medical School.

"In 2010, the poll also asked about e-cigarettes and at that time, only one-third of adults had heard of the product. In this poll, that number jumped to 86 percent," he added.