The taste of the nicotine replacement is under the control of the smoker

Dr Eric Westman

The drops, which can be taken several times a day, provide a quicker nicotine boost than alternatives such as patches or gum.

The idea is that users can get a nicotine hit without the need to smoke, so that the craving to light up diminishes.

Advantage

Dr Eric Westman, from Duke University in North Carolina, is a member of the team that developed the drops.

He told the BBC: "This is just another type of nicotine replacement, like the patch and gum.

"But it could have potential advantages over the patch and gum.

"The most striking advantage is that the taste of the nicotine replacement is under the control of the smoker."

One has to remember that nicotine is a poison, and as this is a liquid we are slightly concerned about the potential for overdose

Amanda Sandford, Action on Smoking and Health

Amanda Sandford, of the anti-smoking charity Action on Smoking and Health, said: "We are in favour of nicotine replacement therapy being available in all sorts of formats to help people quit.

"However, one has to remember that nicotine is a poison, and as this is a liquid we are slightly concerned about the potential for overdose.

"Gums and patches release a carefully controlled among of nicotine into the body. This product would need to be controlled in a similar way."

The researchers are now seeking a larger pharmaceutical company to fund larger trials.