Oregano Extract Ointment for Wound Healing: A Randomized, Double-Blind, Petrolatum-Controlled Study Evaluating Efficacy

October 2011 | Volume 10 | Issue 10 | Original Article | 1168 | Copyright © October 2011

Jennifer Ragi MD,a Amy Pappert MD,a Babar Rao MD,a Daphna Havkin-Frenkel PhD,b Sandy Milgraum MDa

aDepartment of Dermatology, University Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Somerset, NJ bDepartment of Plant Pathology and Biology, Rutgers University, New Brunswick, NJ

the article by Singletary, “the volatile nature of the components of oregano oils can be irritating to mucous membranes and it is recommended that the oils not be applied topically to mucous membrane at greater than 1% concentrations.”28 Also, terpinene, one of the major components of the oregano essential oil, is a hydrocarbon that is classified as a terpene. Terpene was found to be a strong sensitizer,29 and to cause a positive patch test in patients with tea tree oil contact dermatitis.30 We hypothesize that the essential oil-free, water-soluble fraction of oregano would be less sensitizing while retaining the antimicrobial, antioxidant, and anti-inflammatory properties given its high phenolic component.33 34


Institutional review board approval was obtained and study protocol conformed to current ethical guidelines of the 1975 Declaration of Helskini. Written informed consent was obtained from each patient prior to participation in the study. A single center, investigator- initiated, randomized, double-blind, petrolatum-controlled study was performed to determine the effects of an oregano extract ointment versus petrolatum on wound healing. We used 3% water-soluble oregano extract in petrolatum made from Oregano Natural Preservative (ONP), a patented oregano extract product that has all essential oils removed.27


Forty adult patients, 18-75 years old, who underwent excisions for treatment of various dermatologic conditions, regardless of this study, were randomized to one of two groups: 1) the oregano ointment, or 2) petrolatum. Excision sites included the trunk and upper and lower extremities, excluding only the legs, head, and neck. Excisions were performed by resident physicians under clean technique, which included clean gloves, sterile instruments and sterile gauze. Chlorhexidene prep was used and followed by local anesthetics with lidocaine with epinephrine. Buried dermal sutures, using a polyfilament, absorbable material, and simple interrupted or running sutures, using a monofilament, non-absorbable material, were used for skin closure.
table 1
After the excision, the study ointment was applied to the excision site by a medical assistant, out of the site of the evaluating physicians, and then covered with a non-occlusive dressing. On day 0 the study ointment was provided to the patient in a concealed container, and they were instructed to apply the ointment twice-a-day to the site and cover it with a non-occlusive dressing. On day 12 +/-2 days, the patients returned for suture removal, a culture of the excision site was taken, compliance with the ointment and adverse reactions were recorded. A physician evaluated the scar using the Observer Scar Assessment Scale, which grades 5 components of the scar: vascularity, pigmentation, thickness, relief, and pliability on a scale of 1-10 with 1 being normal skin and 10 being most severe or the worst scar imaginable.35, 36 The patient completed a similar scar assessment questionnaire which had the patients rank itch, pain, color, stiffness, thickness, and irregularity on a similar 1-10 scale. The scar was graded using the same patient questionnaire and Observer Scar Assessment Scale on day 45 and day 90 and adverse reactions were recorded. A two-tailed Student t-test using GraphPad Software was used to analyze the data with an a priori level of 0.05.


Forty patients, 23 females and 17 males, aged 22-72 years old, were enrolled in the study. Four patients dropped out of the study for personal reasons and three patients' culture results were not obtained but were evaluated clinically for infection and scar assessments. The oregano ointment group had three out of 16 (19%) cultures test positive for S. aureus, and one out of 16 cultures test positive for methicillin resistant S. aureus (MRSA). The petrolatum group had seven out of 17 (41%) cultures positive for S. aureus, and no cultures were positive for MRSA. One patient of the 17 patients (6%) in the oregano ointment group was treated clinically for cellulitis. Three patients of the 19 patients (16%) in the petrolatum control group were treated clinically for cellulitis. All four patients with cellulitis had a positive culture result for S. aureus.
The average of the Patient and Observer Scar Assessment scores of the oregano and petrolatum groups at day 12, 45, and 90 are shown in Table 1 and 2, respectively. Student's t-test was used for statistical analysis of the scar scores. In the patient scar assessment, the oregano ointment group had lower scores, or closer to normal skin than the petrolatum group in color, stiffness, thickness and irregularity (Table 1). By comparison, the oregano ointment group had a statistically significant improvement over the petrolatum group for color on day 12 (P=0.04) and day 45 (P=0.009, Figure 1). The physician scar assessment showed that the oregano ointment group score was lower or closer to normal skin than the petrolatum group in all five categories: pigmentation, vascularity, thickness, relief, and pliability (Table 2). In the physician scar assessment, the oregano ointment group had a statistically significant improvement over petrolatum in pigmentation on day 12 (P= 0.0014), and pliability on day 90 (P= 0.05, Figure 2).