Can Mayonnaise Kill Lice?

As you have found out when searching online for remedies to eliminate head lice, you’ll find all sorts of products and recommendations—from traditional lice remedies available at drug stores, to online-only alternative products, to home remedies using common household products. One of the most commonly recommended household products is mayonnaise.

That’s right. Some parents suggest spreading your favorite sandwich condiment onto a child’s head in order to kill head lice. The idea is that the thick pasty substance will clog the insects’ breathing mechanism, suffocating each louse to death. You simply wrap the child’s head in some kind of plastic to contain it, and leave the mayonnaise on overnight. Wash it out in the morning and the lice are gone.

There are three problems with this approach. First, there is very little medical evidence that mayonnaise or any other home remedy actually works. The National Association of School Nurses tells people, “There is no scientific evidence that home remedies are effective treatments.”  The Centers for Disease Control and Prevention (CDC) says the same thing: “CDC does not have clear scientific evidence to determine if suffocation of head lice with mayonnaise, olive oil, margarine, butter, or similar substances is an effective form of treatment.”

Just because there is no medical evidence that mayonnaise doesn’t successfully eradicate head lice doesn’t mean it doesn’t work. However, the second problem with the mayonnaise is that, even if it kills head lice, it doesn’t kill lice eggs (nits). Eggs don’t breath and cannot be suffocated. Most lice experts will tell you that killing the eggs is the most challenging part of head-lice treatment. Female lice can lay around 5 eggs per day, and each egg takes 7-10 days to hatch. Lice eggs are almost indestructible (see below), and affix to hair follicles with tremendous strength. Odds are that when you rinse the mayo out of a child’s head, the eggs will still be there and hatch a few days later. The only sure way to remove them is to “nitpick,” or pick them out one by one with a lice comb and a great pair of eyes.

The last reason mayonnaise is not a great idea for lice treatment is that it can be very unsafe to leave a child’s head wrapped in plastic overnight. The risk of an accident is too great. There have been reports of children suffocating from the plastic bags, as well as getting food poisoining from the mayonnaise.

If you have been suffering from lice infestations for far too long, give us a call and get treated today.