Vaseline is sometimes used to try to kill lice. Does it work? Well, yes and no. It can work to kill lice if it left on for eight hours or more. Like any thick substance, Vaseline petroleum jelly can be used to suffocate lice if it is left on the scalp, coating the lice, for eight hours or more. This allows it to circumvent the respiration system of lice who can hold their breath for eight hours.
However, Vaseline is not effective against lice eggs. It can kill lice that are live on the scalp, but it will not kill the eggs. Vaseline is a thick substance that stays in place well and generally does not require a shower cap to keep it in place.
However, using Vaseline to kill lice can also cause acne to those who are prone to it. Vaseline can form a seal over pores, clogging them and causing pimples to form. It is also extremely difficult to remove from the hair.
To get Vaseline or a generic petroleum jelly out of the hair can take a lot of care. Shampoo is generally not enough to remove the substance from hair. Using Dawn or an equivalent dishwashing detergent should be used.
After washing the hair with Dawn two or three times, wash with a strong shampoo like Prell three to four times. This still may not remove all of the Vaseline from the hair, but it will get the hair clean enough to get through another day. The next day, repeat the process and the Vaseline should be out of the hair. The lice eggs may still be left behind, though.
Use a lice comb to come out the lice eggs that still may be in the hair. A plastic or metal lice comb can help you to get rid of the lice eggs that remain in the hair before they can hatch and cause a new lice infestation.