Olive oil is a thick oil that is readily available at every grocery store and mass market store. The thickness of the oil makes it an effective substance to use to suffocate lice. Though the oil is thick, it will warm up slightly when it is exposed to your body heat through your scalp. This can make the oil drip slightly. To keep the olive oil in place more effectively, use a plastic shower cap to keep the oil in contact with the scalp.
One of the problems with killing lice is that lice can suspend their respiration for about eight hours. That means that the olive oil has to stay on the head for eight hours or more in order to outlast that suspension. Once eight hours is reached, the lice have to breathe again, but the olive oil will keep them from getting any air. The lice then die and the live lice infestation is over. However, there may still be eggs, called nits, left behind. Those should be removed from the hair by using a lice comb.
Because nits be be left behind, it's important to use the olive oil several times to ensure that the lice infestation is completely gone, use the olive oil lice treatment every four days. This will ensure that any live lice that hatch from eggs are killed before they can lay more eggs.
The type of olive oil that you use to kill lice isn't that important. However, the smell of the oil after so many hours of having it in the hair can get annoying. If this should occur, switch to using light-tasting olive oil to kill lice. The oil is slightly less thick, but the odor is much lighter.