This is a two-center study aimed to assess the efficacy of Dead Sea Minerals in alleviating symptoms of Psoriasis Vulgaris, in 50 patients undergoing phototherapy. A bilateral left right comparison will be made, after using the study product and the placebo, for 8 weeks, twice daily, on each of the body sides (left right). In addition to the clinical evaluations, skin biochemistry will be studied using non-invasive techniques. The latter will be correlated with the clinical results of the patients. These will serve for future development of diagnostic assays and personalized therapies.

Inclusion Criteria:

• Having 2 symetrical (left right)moderate to severe chronic stable plaque type Psoriasis for at least 6 months and candidates for phototherapy treatment

Exclusion Criteria:

• Volunteers with a known allergy to one of the tested materials or to their ingredients.
• Treatment with medication such as anti-inflammatories, anti-histamines, corticosteroids, systemically or topically applied, unless stopped for 4 weeks prior to the trial in the case of systemic treatment and 2 weeks in the case of topical treatment.
• Volunteers in the process of diagnosis or treatment for cancer / kidney disease / liver disease
• Pregnant or lactating women

Volunteers aged 18-70 diagnosed with moderate to severe chronic stable plaque type Psoriasis for at least 6 months and candidates for phototherapy treatment.