Sense About Science has urged stars not to dip their toes into tricky scientific issues without checking their facts first.
Here are some examples put forward by the charity of dubious science uttered by celebrities - together with the views of its experts.
MELINDA MESSENGER, TV PRESENTER
"Why should I allow my body or my children to be filled with man-made chemicals, when I don't know what the health effects of these substances will be."
Dr John Hoskins, toxicologist: "Away from the high doses of occupational exposure a whole host of unwanted chemicals finds its way into our bodies all the time.
"Most leave quickly but some stay: asbestos and silica in our lungs, dioxins in our blood. The most important thing is dose: one aspirin cures a headache, a hundred kills.
"The chemical baggage we carry is very small. It is only because of the great advances in analytical chemistry that we are able to detect it's there at all."
CHRIS DE BURGH, MUSICIAN
"...he was in serious pain, just below the knee, and I felt the area above had been traumatised. I started feeling and I'd say within 20 minutes, he was walking again. It took away the pain."
Prof Peter McNaughton, pharmacologist, University of Cambridge: "Sensation of pain is very subject to suggestion, so I am not surprised Chris's friend 'could be made to feel no pain'.
"That does not mean that there was any change to the injury that caused the pain, but more likely a reduction in the extent to which he noticed the pain."
CAROLE CAPLIN, LIFESTYLE GURU
On how to prevent breast cancer by giving women more information about "the importance of keeping the lymph system clear and unclogged".
Prof Michael Baum, emeritus professor of surgery, University College London: "Carole's idea of keeping the lymph system "clear and unclogged" has no meaning whatsoever.
"It is not based on knowledge of anatomy or physiology of the human body, let alone of breast cancer."
HEATHER MILLS MCCARTNEY, FORMER MODEL
"...every day there's a new report warning that obesity levels in children are out of control... The fact that those children who drink the most milk gain the most weight should cause alarm bells to be ringing everywhere. It isn't and milk is still being pushed as essential for children."
Dr Philip Coan, physiologist, University of Cambridge: "It is not true to say that children who gain the most weight are doing so because of milk consumption.
"A US study looked at milk consumption in two to five-year-olds over a three-year period.
"It found no link between increases in child weight and increases in drink consumption.
"In relation to milk, child weight was not linked to whether the children drank full-fat, semi-skimmed or skimmed milk."
JOANNA LUMLEY, ACTRESS
"We cannot go on force-feeding animals chemicals and growth stimulants the way we are. Why do you think cancer is roaring ahead at the moment?"
Prof John Toy, medical director, Cancer Research UK: "Cancer is not 'roaring ahead'. It is more common because mostly people are living longer.
"It is essential that 'cancer-causing' claims are based only on scientifically proven facts, not scaremongering.
"There is no definitive evidence that controlled food additives cause cancer.
"We do know that half of cancers are caused by lifestyle factors such as being overweight."