Though vinegar can be used in the removal of lice, it does not kill them.
Researchers at the Center for Vector-Borne Diseases at the University of California, Davis tested the potential value of six different commonly used home remedies including vinegar, petroleum jelly, mayonnaise, isopropyl alcohol, olive oil, and melted butter and found none of them to be an effective treatment for lice infestations. Vinegar did not kill the lice or the eggs, and did not prevent them from laying eggs. [Journal of Pediatric Nursing]
If Vinegar Doesn’t Work Why Is It a Commonly Suggested Remedy?
Female lice use a very hard substance similar to cement to attach their eggs, known as nits, to the hair shaft. Though vinegar does not kill lice, there are a few extension services that suggest rinsing hair with vinegar to help loosen the hard substance that holds lice eggs tightly to the hair. [The Ohio State University Extension]
Lice do not survive long off the hair of their host so the most effective first line of defense when faced with a lice infestation is to physically remove the nits with a special comb. Once all lice have been removed the infestation needs to be managed by washing anything that the individual has come in contact with at a temperature of 130-140 degrees for a minimum of ten minutes and dried on the highest heat setting for twenty minutes.
Lice are more prevalent in children and prefer longer hair. The primary way to kill lice is with specially formulated lice killing shampoo, and the removal of nits is best done by hand with a metal comb.
Takano, Lee M. “Home Remedies to Control Head Lice: Assessment of Home Remedies to Control the Human Head Louse, Pediculus Humanus Capitis (Anoplura: Pediculidae).” Journal of Pediatric Nursing 19.6 (2004): 393-98. Print.
Head Lice FAQ – ENT/rsc-8.” North Carolina Cooperative Extension: Home. N.p., n.d. Web. 14 May 2010. http://www.ces.ncsu.edu/depts/ent/notes/Urban/lice-faq.htm.
& . “Head Lice, Bulletin 893-01, Nit-Picking Step by Step .” Ohioline. N.p., n.d. Web. 14 May 2010. http://entomology.osu.edu/schoolipm/IPMfiles/Factsheets/head_lice.pdf.