Hypertrophic scar, a disfiguring tissue reaction to trauma, occurred in around 20 % of the population. The patients with hypertrophic scar usually seek medical assistance not just for the annoying appearance but mostly due to the intractable itchiness. There have been a variety of effective methods to alter the appearance of the scar. However, the treatments for itching from hypertrophic scar are scarce. In 2009, P.Gazerani used Botox to treat histamine-induced itch with favorable results. In the clinical setting, however, the efficacy of Botox to treat itch from hypertrophic scar was yet to be proven. Therefore, the goal of this study is to conduct a randomized controlled trials about using Botox to treat itch from hypertrophic scar.

Inclusion Criteria:

1. The patients undergoing laparotomy and thoracotomy in Veterans General Hospital in Kaohsiung (VGHKS) during 2003/1/1~2012/12/31
2. Hypertrophic scars containing more than two itchy sites with itchiness scale >3
3. Good wound healing condition, no infection sign
4. Age older than 20 year-old

Exclusion Criteria:

1. Allergy to Botulinum toxin
2. Inability to express self-willingness
3. Pregnancy