Objective To investigate the effect of Heijiangdan Ointment （Ointment of carbonized human hair and yolk） on the Ⅳ degree radiation dermatitis in mice and its influence on the histomorphological and collagenous changes of wound. Methods Forty-eight Wistar female mice with the Ⅳ degree radiation dermatitis induced by 60Co γ-ray 6 000cGy one time radiation were randomized into 4 groups with 12 in each. The 4 groups were treated with the application of Heijiangdan Ointment

recombinant human epidermal growth factor （rhEGF） solution

Trolox solution

and normal saline respectively. A blank group was set up with 12 mice in it and treated with application of normal saline. The treatment for all groups was once a day and 21 days in succession. On the 1st

6th

11th

16th

and 21st day of treatment

the area of ulcer of all groups were measured

and on the 11th and 21st day

the ulcer tissues were collected and stained by HE staining

Victoria blue with Ponceau S staining

and Sirius red staining for observing the changes in histomorphology and collagen of the wound. Results On 6th

11th

16th and 21th day

the area of skin ulcer in Heijiangdan Ointment group and rhEGF group was smaller than that in the model group （P<0.05）

the area of skin ulcer in Heijiangdan Ointment group was smaller than that in the Trolox group （P<0.05） but bigger than that in the rhEGF group （P<0.05）. After the treatment for 21 days

the inflammatory cells in wound tissues in the Heijiangdan Ointment group was less than those in the model group

while the elastic fibers

collagenous fibers and collagens typeⅠand type Ⅲ were more than those in the model group. Conclusion Heijiangdan Ointment may speed up the ulcer healing of the Ⅳ degree radiation dermatitis

reduce the inflammatory reaction in wound

and promote the repair of elastic fibers and collagen.