Disturbances in biophysical properties of the skin during irritant reactions induced by exposure to chemicals may be assessed by several non-invasive methods. The most popular one involves determinations of transepidermal water loss, stratum corneum hydration, skin pH and evaluation of erythema, pigmentation and skin blood flow. Non-invasive techniques are also applied to assess individual skin susceptibility to irritants. In dermatology and cosmetology they provide information about efficacy and safety of medicines, cosmetics and hygiene products. Determinations of skin parameters may also be useful in diagnosing and monitoring of various dermatoses and in the observation of changes in skin properties caused by the disease. Med Pr 2010;61(4):457-466