The yolk of an egg is rich in fats and proteins and is naturally moisturising, while the white, which contains bacteria-eating enzymes, removes unwanted oils.
For normal hair, use the entire egg to condition hair; use egg whites only to treat oily hair; use egg yolks only to moisturise dry, brittle hair. Blend about 1/2 cup of whichever egg mixture is appropriate for you and apply to clean, damp hair. If there isn't enough egg to coat scalp and hair, use more as needed. Leave on for 20 minutes, rinse with cool water and shampoo hair. Whole egg and yolks-only treatments can be applied once a month, while whites-only treatment can be applied every two weeks.