According to the Mayo Clinic, head lice is the second most common communicable disease (after the common cold) among schoolchildren. These tiny insects are parasites that live and feed on the blood from a human scalp. Because lice spread easily from person to person via close contact, contracting lice is in no way a sign of poor hygiene.

Over-the-counter treatments and prescription medications will rid your child’s head of lice, but most contain potentially toxic pesticides—their goal is to kill bugs, after all. Instead, try a natural, homemade lice shampoo designed to smother the critters. Combine mayonnaise, olive oil, or coconut oil with a few drops of essential oil (like tea tree, eucalyptus, or peppermint), mix in a capful of shampoo, and thoroughly coat the scalp and hair. Cover tightly with a plastic shower or bathing cap for one hour; then wash two or three times in hot (not scalding) water. Rinse with vinegar and comb with a fine-tooth, lice-specific comb. And don’t neglect to wash all exposed bedding, stuffed animals, and clothing in hot water and dry on high heat.