Skip to main content

The Globe and Mail

Can my child’s lice shampoo really cause cancer?

The question: My kid picked up lice at school, again! I don't want to use cancer-causing shampoos, what else can I do?

The answer: Very few school health issues get a parent's skin crawling (sometimes literally!) like the topic of lice.

Head lice, as many parents already know, are small insects about the size and colour of a sesame seed, that are commonly found on the scalp of preschool and elementary school children. Pediatricians most often recommend treatment with a medicated shampoo containing permethrin (which goes by the brand name Nix or Kwellada) or pyrethrin (R&C Shampoo).

Story continues below advertisement

Fortunately, these Health Canada-approved therapies are safe to use in children with no evidence to suggest they cause cancer when used as directed.

However, some lice are becoming resistant to these medical insecticides. This may be one explanation for your recurring problem. The more likely scenario is that some kids at the school are not receiving any treatment at all and keep re-infecting the class.

If you are looking for effective alternative therapies that do not contain medical insecticides, consider cyclomethicone or dimethicone (look for the brand names Resultz and NYDA). These treatments are available at your local pharmacy.

Contrary to popular belief, removal of the nits is not required. Although parents may choose to remove the nits for cosmetic purposes, the recommended treatments will eradicate both the live lice and eggs. I suggest application of a second treatment one to two weeks later as "insurance" to kill any lucky lice or eggs that may have evaded the first treatment.

It is not clear whether there is any additional benefit to cleaning school and household items, as lice are spread through direct head-to-head contact. That being said, washing hats, hoodies, bedding and hairbrushes in hot soapy water seems prudent. More extensive disinfection is not needed.

Fortunately, lice are more of an annoyance than a serious medical problem, and children should be allowed to return to daycare and school immediately after receiving treatment.

But parents, please avoid home remedies like mayonnaise, petroleum jelly and tea tree oil, as these products have not been found to be effective at eradicating lice. You can bet that trying to get a mess of mayo out of your child's hair isn't any more fun than lice.

Story continues below advertisement

Dr. Michael Dickinson is the head of pediatrics and chief of staff at the Miramichi Regional Hospital in New Brunswick. He's a staunch advocate for children's health in Atlantic Canada through his involvement with the Canadian Paediatric Society.

Click here to submit your questions. Our Health Experts will answer select questions, which could appear in The Globe and Mail and/or on The Globe and Mail web site. Your name will not be published if your question is chosen.

The content provided in The Globe and Mail's Ask a Health Expert centre is for information purposes only and is neither intended to be relied upon nor to be a substitute for professional medical advice, diagnosis or treatment.

Report an error Editorial code of conduct
As of December 20, 2017, we have temporarily removed commenting from our articles. We hope to have this resolved by the end of January 2018. Thank you for your patience. If you are looking to give feedback on our new site, please send it along to If you want to write a letter to the editor, please forward to