The study aims to evaluate the clinical efficacy and safety of the modified Qing-Ying Decoction (mQYD) for the treatment of subacute and chronic atopic dermatitis (AD) in children when compared to the placebo control through examining the clinical symptoms, quality of life, gut microbiome, and Chinese medicine body constitution.

This is a parallel, randomized, placebo-controlled, double-blind clinical trial. Eligible subjects will be randomly allocated to receive oral mQYD granules or it's placebo granules. Subjects will have 12-week of treatment, and then a 4-week follow-up.

The subjects will come for a screening visit at week 0 (baseline), then at week 6, week 12, and week 16 for Chinese medicine practitioner (CMP) investigators assessments. Eczema Area and Severity Index (EASI), Children's Dermatology Life Quality Index (CDLQI), Patient-Oriented Eczema Measure (POEM), and Chinese Medicine body constitution types will be assessed and filled up at different timepoints. They will receive oral herbal mQYD or placebo granules for 12 weeks and then be followed up 4 weeks after the treatment. Registered CMPs will provide consultation under Chinese medicine theory. Study medication compliance and adverse events will also be assessed at each visit. Besides, they need to record the food taken in a diary before the day for taking faecal specimen for gut microbiome analysis.

Inclusion Criteria:

1. Age of 4 to 17 (Chinese only);
2. With EASI ≥ 10;
3. Subacute and chronic atopic dermatitis presenting with dry, scaly, erythematous papules and plaques; and
4. Provide written informed consent form (signed by one of their parents)

Exclusion Criteria:

1. History of allergy to Chinese medicines;
2. AD with Yang deficiency in syndrome differentiation, such as pale looking, always feeling cold, fatigue, chronic diarrhea with loose stool, urinary disorders such as urinary difficulty, excessive urination or incontinence
3. Known overt bacterial infections in the skin;
4. Known pregnancy;
5. Known severe medical conditions, such as cardiovascular, liver or renal dysfunction or Diabetes Mellitus;
6. Having used oral corticosteroids, oral antibiotics, other immunosuppressive or any preparation of oral herbal medicines for the treatment of AD in the past month;
7. Having been diagnosed with scabies, allergic contact dermatitis, seborrheic dermatitis or psoriasis; and
8. Has taken anti-coagulant or anti-platelet drugs in the past month.
9. Has taken any probiotics, prebiotics in the last month
10. Known history of glucose-6-phosphate dehydrogenase (G6PD) deficiency