A quantitative computerized morphometric method was developed and used for evaluating the abundance of psoriatic microvilli on keratinocytes. Scanning electron micrographs of keratinocytes obtained from psoriatic patients were prepared. The area of microvilli on their surface was quantified morphometricaliy before and after the following treatments: bathing in the Dead Sea daily for 28 consecutive days, or immersion of one elbow in a warm solution of Dead Sea salts (2.5% or 5%) for 30 min daily over 28 days. Clinical evaluation of the patients was performed by comparing plaque area from drawings prepared by the physician on graph paper, or by scoring the following parameters: erythema, infiltration and desquamation. Bathing in the Dead Sea reduced the area of psoriatic microvilli by 64.3%, while using the Dead Sea salts at home reduced the area by 34.8% using the 2.5% solution and by 34.7% using the 5% solution.