With hangovers it is just a waiting game, research suggests
It may feel like the aspirin, fry-up or even "hair of the dog" is helping to alleviate that hangover caused by over-indulging the night before.
But in fact there is no such thing as a "cure" for a hangover, say researchers from Indiana University in the US.
It is one of six Christmas-related myths which been debunked in the British Medical Journal.
The team trawled through the medical literature and internet for evidence on a range of commonly held beliefs.
HAVE YOUR SAY
We all know our own bodies and take sensible advice accordingly
Colin, Plymouth, UK
"Both physicians and non-physicians sometimes believe things about our bodies that just are not true," wrote Dr Rachel Vreeman and Dr Aaron Carroll.
"Examining common medical myths reminds us to be aware of when evidence supports our advice."
So what did they find?
An internet search flagged up endless methods claiming to cure a hangover from aspirin to bananas to Vegemite and water.
But there is no scientific evidence of an effective cure or method of preventing hangovers, the researchers said, despite many trials being carried out on both traditional and complementary medicines.
Keeping teetotal or drinking in moderation is the only way to avoid a hangover, they concluded.
EATING LATE AND GAINING WEIGHT
Putting on pounds in the festive period almost seems inevitable but to avoid unwanted weight gain it has been suggested that people avoid eating late at night.
The idea is that you cannot burn off the calories if you are asleep.
But this is not supported by the evidence.
A Swedish study found that obese women were more likely to eat at night, but they also ate more in general.
In another study of more than 2,500 patients, eating at night was not associated with weight gain but eating more than three meals a day was.
Ultimately, taking in more calories makes you gain weight whenever you eat them, the researchers said.
SUGAR AND HYPERACTIVITY
With Christmas comes selection boxes and a host of sweet treats but parents need not fear their children climbing the walls.
It is commonly thought children become hyperactive after eating sugar
Regardless of what parents might think, sugar does not cause hyperactive behaviour.
At least 12 randomised controlled trials looking at levels of sugar and behaviour - even in children with attention deficit hyperactivity disorder - were unable to detect any difference.
Scientists also found that when parents think their child has had a sugary drink they rate their behaviour as more hyperactive - so it is all in the mind.
HATS AND THE COLD
We've all been told to put a hat on in winter because most heat is lost through the head.
The researchers even found that the US Army Field manual for survival recommends covering your head in cold weather because around 40-45% of body heat is lost through the head.
A recent study, however, showed there is nothing special about heat loss from the head - any uncovered part of the body would lose heat.
Scrutiny of the literature shows this myth probably originated with an old military study in which scientists put individuals in arctic survival suits (but with no hat) and measured their body temperature in extreme conditions.
If the experiment had been done with the participants wearing only swimsuits they would not have lost more than 10% of their body heat through their heads, the researchers said.
Poinsettias are a common Christmas decorative feature but many believe they are poisonous.
In reality they are fairly harmless.
Of 22,793 cases of poinsettia exposure reported to poison control in the US, there were no deaths and 96% did not require medical treatment and none resulted in considerable poisoning.
A study in rats could not find a toxic level of the plant sap.
SUICIDES AT CHRISTMAS
"The combined stresses of family dysfunction, exacerbations in loneliness, and more depression over the cold dark winter months are commonly thought to increase the number of suicides," said Dr Vreeman.
But, although the holidays may be difficult for some, there is no good evidence to suggest a peak in suicides.
Also people are not more likely to commit suicide in the dark winter months - around the world suicides peak in warmer months, the researchers said.