Think twice about blaming sweets for your out-of-control children this festive season, and those added kilos might not be due to an ill-advised late-night meal. As for an aspirin to cure a hangover? Forget it.

That’s the advice of two researchers seeking to debunk some common medical myths that crop up during the holidays but have little scientific backing, they say.

“In the pursuit of scientific truth, even widely held medical beliefs require examination or re-examination,” Rachel Vreeman and Aaron Carroll of the Indiana University School of Medicine wrote in the British Medical Journal.

“The holiday season presents a further opportunity to probe medical beliefs recounted during this time of year.”

The pair combed through previous scientific studies and searched the Web for evidence to support or refute common beliefs such as one tagging poinsettia plants as toxic. Don’t worry, they aren’t.

Many parents think sugar from sweets, chocolates and other sources makes children hyperactive but research shows this is not the case. Rather, the link is most likely in the parents’ minds, the researchers said.

“Regardless of what parents might believe, however, sugar is not to blame for out-of-control little ones,” the researchers wrote.

People fret over the holidays about putting on the kilos after so many festive meals. But eating late at night does not pose a problem when it comes to gaining weight, according to the studies the researchers reviewed.

Another myth is a mistaken belief that most body heat escapes through the head, putting undue importance on woolen hats when temperatures drop, they wrote.

“If this were true, humans would be just as cold if they went without trousers as if they went without a hat,” they said. “But this patently is not the case.”

And for revellers confident they have the trick to prevent or cure a hangover, the researchers say moderation is the only way to escape that pounding headache.

“From aspirin to bananas to Vegemite and water, Internet searches present seemingly endless options for preventing or treating alcohol hangovers,” they said.

“No scientific evidence, however, supports any cure or effective prevention for alcohol hangovers.”