I will never forget coming home from school one day with more than my homework. My usually calm mother reacted with horror and shame and a fit- literally-of fine-tooth-comb nit-picking (after dousing my head with kerosene). Decades later, while working as a nurse with farm workers in California's Central Valley, I remember a young visitor to our trailer clinic who climbed into my lap. I found myself looking not into her beautiful brown eyes, but a mass of nits (eggs) in her hair.

As always, I went to the community women to see what they were using for head lice. Their homemade boric acid bait had been successful against cockroaches. This time, however, all they knew was "lindano," or lindane (Kwell and others), which in the late 1960s was readily available over the counter. And although lindane, one of the most toxic products ever used for the control of lice, is no longer considered a first-line treatment for lice in the United States, it has been replaced by other toxic insecticides, such as pyrethrins and pyrethroids (Nix, Rid, and others) and malathion (Ovide and others).

Head lice will never make the parasite hall of fame: they don't kill the host or cause other diseases. Yet they remain a persistent problem (even though some providers shrug off infestation as a minor public health concern), and since head lice are the most common communicable childhood health problem after the common cold, controlling them leads to avoidable exposure of children to toxic substances.

While infestation with lice isn't fatal, deaths from asthma and bronchospasm in users of pyrethrins have occurred. Lindane is a potent neurotoxin that can cause seizures and has been linked to several deaths. Permethrin can cause itching, redness, and swelling on the scalp and can trigger asthma and allergies. An unknown amount of exposure to children occurs from prophylactic use, when a parent learns of an outbreak and uses a toxic shampoo without evidence of infestation.

Head lice can be controlled without insecticides. More than 20 years ago it was suggested that one could just dissolve the gluelike material that bonds nits to the hair shaft-simply loosen the glue and comb out the nits. This is just what shampoos made with enzymes from natural vegetable extracts do. The best example I've found is Lice B Gone (from Safe Effective Alternatives, http://www.licebgone.com), a highly effective treatment that is inexpensive and simple to use, usually requiring only one 60-minute treatment. It is nontoxic, can be used repeatedly without harm (although that isn't usually necessary), and can be safely used to treat pregnant or nursing women as well as children. Another enzyme-based treatment is Lice Away Enzyme Shampoo (Nature's Best, http://www.naturesbestenzyme.com).

Why are these products not on every drug store and supermarket shelf in the country? Primarily because of human resistance to change. Remember that the British navy refused to follow James Lind's recommendation that citrus be given to sailors until 42 years after he published the findings of his study proving that it prevented scurvy. Ignaz Semmelweis was ridiculed when he suggested that doctors wash their hands and change bloody sheets between patients to prevent puerperal sepsis (childbed fever).

Treating head lice can be a simple act of grooming. Florence Nightingale saved thousands of British soldiers in Scutari during the Crimean War using basic public health principles of cleanliness. I foresee a day when the same is true of controlling lice. Parents are eager for safe products for their children.

Health professionals should ask themselves why they are willing to recommend a poison but balk at a simple, over-the-counter product that in almost all cases produces nit-free children after one treatment. The anxiety and inappropriate practices surrounding infestation with head lice will disappear when it is finally seen as the easily solvable problem it is. All it will take is for humans to do that most-difficult thing-change their thinking.