In 2003 the European Agency for the Evaluation of Medicinal Products amended the summary product characteristics for oral isotretinoin to standardise information provided from the different countries of the European Community. The Committee for Proprietary Medicinal Products recommended that among others, exclusively severe forms of acne (such as nodular or conglobate acne or acne at risk of permanent scarring) resistant to "adequate courses" of standard therapy with systemic antibacterials and local therapy should benefit from oral isotretinoin. However, no indication was provided on what were considered adequate courses or the possibility given to use oral isotretinoin as first line treatment. The aims of the present report were: 1) to provide a specialist view on when it is appropriate to introduce oral isotretinoin as a second line therapy for acne, taking into consideration optimum dosage and duration of systemic antibiotics prior to the start of the oral isotretinoin, and 2) to support the use of oral isotretinoin as first line therapy in specific cases for acne in clinical practice. The recommendations are based on an exhaustive literature review as well as on the personal experience of the members of an European panel of acne specialists. The EEP agreed with the decision made by the CPMP that oral isotretinoin should be administered as 2nd line therapy in those cases of severe acne, which were resistant to or which did not respond successfully to an initial combination regimen with systemic antibiotics and topical treatments (topical retinoids +/- benzoyl peroxide). However, the members emphasized that a number of prognostic factors, as well as psychosocial morbidity should be taken into account when choosing the regimen and that these factors may influence the use of oral isotretinoin as first line therapy.