Find out about COVID-19, COVID-19 vaccines, and Mayo Clinic patient and visitor updates.
Featured conditions Brain tumor, breast cancer, colon cancer, congenital heart disease, heart arrhythmia. See more conditions.
Featured conditions
Head lice feed on blood from the scalp. The female louse lays eggs (nits) that stick to hair shafts.
Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission.
Check out these best-sellers and special offers on books and newsletters from Mayo Clinic Press.