The complementary therapies with the most robust evidence of efficacy for treatment of psoriasis include the Chinese herbal medicine Qing Dai (indigo naturalis) and acupuncture, along with curcumin, dietary modification, fish oil and meditation. American authors analysed results from 44 RCTs, 13 uncontrolled trials and 3 meta-analyses. Compared with placebo, application of topical indigo naturalis (studied in 5 RCTs with 215 participants), showed significant improvements in the treatment of psoriasis. A meta-analysis of 13 RCTs also showed significant improvement of psoriasis comparing acupuncture with placebo.

Complementary and Alternative Medicine Therapies for Psoriasis: A Systematic Review. JAMA Dermatol. 2018 Nov 1;154(11):1330-1337.