The present paper deals with the effects of ozonized autohaemotherapy on the human hair cycle in subjects suffering from androgenetic alopecia. The microscopic observation of hairs (trichogram) of 42 subjects (age range = 17-40 years) was carried out before and after cycles of ozonized autohaemotherapy according to the European scientific protocol. The dosage of ozone was 2500-3000 micrograms for each treatment, one cycle consisting of 16 treatments. Results showed a marked improvement of the hair cycle.