Glycyrrhiza glabra L. has been used in herbal medicine for skin eruptions, including dermatitis, eczema, pruritus and cysts. The effect of licorice extract as topical preparation was evaluated on atopic dermatitis. The plant was collected and extracted by percolation with suitable solvent. The extract was standardized, based on Glycyrrhizinic acid by using a titrimetry method. Different topical gels were formulated by using different co‐solvents. After standardizing of topical preparations, the best formulations (1% and 2%) were studied in a double–blind clinical trial in comparison with base gel on atopic dermatitis over two weeks (30 patients in each group). Propylene glycol was the best co‐solvent for the extract and Carbopol 940 as gelling agent showed the best results in final formulations. The quantity of glycyrrhizinic acid was determined 20.3% in the extract and 19.6% in the topical preparation. Two percent licorice topical gel was more effective than 1% in reducing the scores for erythema, oedema and itching over two weeks (p<0.05). The results showed that licorice extract could be considered as an effective agent for treatment of atopic dermatitis.

Background: Topical retinoids are considered first-line therapy in the treatment of acne vulgaris, yet can be associated with cutaneous irritations. Combination therapy with natural preparations could be effective in treatment and decreasing adverse events. Objective: The aim of this study was to compare the efficacy and safety of the combination of tretinoin (TR) cream (0.05%) and Aloe vera topical gel (50%) with TR and vehicle. Material and methods: The randomized, double-blind, prospective 8-week trial evaluated inflammatory and non-inflammatory lesion scores and tolerability in 60 subjects with mild to moderate acne vulgaris (global acne grading system scale). Results:Several formulations of A. vera leaf gel were prepared and the most stable one was selected for clinical study based on physicochemical evaluations. The combination therapy showed superior efficacy to TR and placebo. TR/Aloe vera gel (AVG) was significantly more effective in reducing non-inflammatory (p = 0.001), inflammatory (p = 0.011) and total (p = 0.003) lesion scores than control group. The highest percentage of adverse cutaneous effect was reported for scaling. At the end of study, erythema in the TR/AVG-treated group was significantly less severe (p = 0.046). Conclusion: The combination TR/AVG was well tolerated and significantly more effective than TR and vehicle for the treatment of mild to moderate acne vulgaris.