Many people swear by a late night tipple to help them fall asleep.
One in 10 people have problems sleeping
However, a study by scientists in Canada suggests they may, in fact, be fooling themselves.
They have found that although a nightcap can help people escape to the land of nod more quickly, their sleep is unlikely to be a restful one.
They are more likely to wake up during the night and early the following morning, and are less likely to have the deep sleep they need.
Dr Shawn Currie and colleagues at the University of Calgary based their findings on a study of 63 recovering alcoholics.
People who have problems with alcohol often have difficulty sleeping, both when they are actively drinking and when they have stopped.
In particular, many find it difficult to fall asleep at all and to remain asleep when they finally drift off.
"Sleep has a reputation among the recovering community of being one of the last things that fall back into place for an individual," said Professor David Hodgins, from the University of Calgary.
"It's also recognised as a potential precipitant of relapse."
This latest study has found these problems can last for months after they stop drinking.
However, the researchers also found that over half of those involved in the study had sleep problems long before they became hooked on alcohol.
This compares to rates of about 10% to 15% in the general population.
The researchers were obviously unable to make a direct link between problems falling asleep and an increased risk of alcohol dependence.
"Although we cannot infer any causal connection between insomnia and alcoholism from this data, it is hard to ignore such a high rate of pre-existing sleep problems in this sample," said Dr Currie.
Poor night's sleep
He warned that a late-night tipple is often a false economy for people trying to get a good night's sleep.
"Three or more drinks will cause the average person to fall asleep sooner than usual," he said.
"However, falling asleep faster is the only real benefit of alcohol for sleep.
"The more prevalent, disruptive effects include more frequent awakenings, worse sleep quality, reduction of deep sleep, and earlier than usual waking times leading people to feel they did not get enough sleep."
He added: "These findings warn against developing the habit of having, for example, a glass of wine to help go to sleep."
The researchers believe their study could also help recovering alcoholics.
They said the findings highlighted the need to provide greater help to these people to help them to get a good night's sleep.
"These findings lead to the idea of targeted interventions with alcoholics.
"Despite the very comprehensive and broad-based nature of most treatment programmes, very, very few of them tackle sleep as an issue.
"But sleep is obviously a problem for some people and a relevant area of intervention," he said.
"It may be that sleep can be improved in recovering alcoholics through using an approach that emphasises good sleep habits, relaxation and stress management."
The study is published in the journal Alcoholism: Clinical & Experimental Research.