Abstract: Objective Research of the hair damage due to perming, combing and strething can be of important volue for forensic hair individual identification. Methods The normal human hairs were treated with perming combing and stretching, and the keratins of the damage hair were analysed by using SDS-PAGGE and laser densimeter. Results Perming, combing and stretching brought about hair damage;The keratins of the damage hair were obviously reduced at the rang of molecular weight of 67 000～43 000 dalton. Conclusion The loss of the damage hair keratins were increased with the degree of the hair damage.

Key words: perming, combing, stretching, hair damage, keratins