The article focuses on problems of treating patients with various forms of acne using systemic isotretinoin (SI). The results of a prospective, noncomparative open study of the efficacy and safety of generic SI (Sotret) in 23 patients with vulgar, conglobata and inverted acne were reported. The severity of the process was assessed according to the presence and number of acne and post-acne elements. The intensity of acne symptoms was assessed using a grading system before and during treatment. Sotret was administered as monotherapy at a dose corresponding to the clinical severity of the process. Application of external moisturizing and sunscreen agents was allowed. The study revealed that administration of Sotret in patients with moderate acne vulgaris at the starting dose of 0.3-0.4 mg/kg of body weight with treatment duration of up to 4-5 months allows one to achieve clinical cure with complete disappearance of the primary elements of the rash in 90% of patients. Administration of Sotret in patients with severe acne vulgaris at a dose of 0.5-0.7 mg/kg of body weight with treatment duration up to 6 months resulted in clinical cure in 75% of patients and significant improvement in 25% of patients. Administration of Sotret in group of patients with acne conglobata and inverted acne, including Hoffmann's Perifolliculitis capitis abscedens et suffodiens, at a dose of 0.75-1.0 mg/kg of body weight for 6 months resulted in a significant clinical improvement in all patients. Safety and good tolerability of a course of treatment with Sotret in patients with various forms of acne was demonstrated.