This study is to evaluate the effectiveness of peritoneal lavage with super-oxidised solution in reducing surgical site infection after open surgery for perforated appendicitis.

Open appendicectomy for perforated appendicitis is associated with significant morbidity from surgical site infection. The standard practice is to perform peritoneal and wound lavage using normal saline solution. The investigators propose the use of superoxidized solution for peritoneal and wound lavage to decrease the incidence of surgical site infection.

Superoxidized solutions contain hypochlorous acid (HOCl) which has bactericidal properties. The reactive oxygen species that is produces damages cell wall membrane of unicellular organisms, however remains safe when in contact with human or animal tissue. It is commonly used for topical treatment of wounds.

Inclusion Criteria:

1. Patients between the age 13 and 70 years
2. Diagnosed with perforated appendicitis intra-operatively
3. Undergo open appendicectomy via Lanz incision

Exclusion Criteria:

1. Surgical technique: Laparoscopic appendicectomy or mid-line laparotomy
2. Patients on steroid treatment and immunosuppressant therapy.

The study participants, healthcare providers who attend to the participants during the trial (surgeon and nurses), outcome evaluators (surgical doctors and nurses) and data collectors will be blinded to the allocation.

The sterile study solution (super-oxidised solution) or placebo (normal saline 0.9%) will be stored in a similar storage container and will have the same clear appearance.