Efficacy and Safety of a Botanical Total Coumarin (TC) Cream in Treating Patients With Psoriasis Vulgaris (PLANTCOAT-III)

Inclusion Criteria:

* Age of 18-70 years old. Both men and women, and members of all races and ethnic groups
* Consistent with the diagnostic criteria of stable phase psoriasis vulgaris, and have at least two target lesions suitable for evaluation
* Women of childbearing age must be using birth control strategies defined by one of the following: 1) a barrier method (condom) and/or 2) oral contraceptives, during the 8-week study period.
* ISGA score ≥ 2 (at least mild severity)
* BSA (stable stage group): 1%≤ to ≤20%
* Signed a written informed consent document
* No additional exposure to the sun

Exclusion Criteria:

* Subjects in pregnancy, preparing for pregnancy, or breastfeeding
* History of hyperergic or photosensitivity
* History of complicated cardiovascular diseases, cerebrovascular diseases, severe primary diseases of the hepatic, kidney, and hematopoietic system, or patients with psychiatric disorders
* History of photosensitive diseases such as porphyria, chronic actinic dermatitis, Xeroderma pigmentosa
* Within 4 weeks prior to randomization, patients have taken treatment with the following approved or investigational psoriasis therapies on the target lesions:

  * Topical treatments
  * PUVA, UVB, or Grenz ray therapy.
  * Any systemic treatments other than biologicals with a possible effect on psoriasis (e.g., corticosteroids, vitamin D analogues, hydroxycarbamide, azathioprine, methotrexate, cyclosporine, other immunosuppressants).
  * Any types of other investigational therapies for psoriasis
* Within 3 months prior to randomizations, patients have taken systemic treatments with retinoids or biological therapies (marketed or otherwise) with a possible effect on psoriasis (e.g., alefacept, efalizumab, etanercept, infliximab).
* Planned initiation of, or changes to, concomitant medications that could affect psoriasis (e.g., beta blockers, anti-malaria drugs, lithium) during the double-blind phase of the study.
* History of allergic reactions attributed to compounds of similar chemical or biologic compositions to Coumarins.