Acne is considered as a common chronic skin disease, which affects up to 80% of the population aged 12 to 24 years. At the same time, the incidence of acne is 8 and 3% in the age groups 25—34 and 35—44 years, respectively, and severe forms account for up to 20% of all clinical cases. А systemic retinoid isotretinoin is the treatment of choice for severe and moderate acne. Objective — the study was aimed at evaluating the efficacy and safety of various regimens of treatment with isotretinoin produced using Lidose technology in patients with adolescent acne, adult acne, and acne urticata. Material and methods. The study included 182 patients with different clinical forms and severity of acne: adolescent acne — 122 (67%) patients, adult acne — 44 (24.2%), and acne urticata — 16 (8.8%). The patients were divided into three groups depending on the regimen of treatment with isotretinoin. In Group 1 (n=97) patients, daily dose (initial dose) of Acnecutan was 0.6—0.8 mg/kg and it was reduced after stabilization of the process to 0.4—0.5 mg/kg for 2—3 months and 0.2—0.3 mg/kg for 2—3 months followed by withdrawal of the drug. The course dose of Acnecutan was 100—120 mg/kg. The average duration of the course was 8—10 months (in some cases, up to 12 months). Group 2 (n=51) patients were treated without reducing the dosage. Daily dose of Acnecutan was 0.5 mg/kg, course dose was about 100 mg/kg, duration of treatment was 8—10 months. Group 3 (n=34) patients received low-dose treatment with isotretinoin, 0.3—0.4 mg/kg, the duration of treatment was 1 year. Results. In the case of severe adolescent acne (nodular, cystic, conglobata) and severe papulopustular acne, the course of Acnecutan at a dose of 0.6—0.8 mg/kg followed by gradual dose reduction is the most appropriate treatment. In the case of moderate adolescent papulopustular acne, the course of isotretinoin without dose reduction (0.5 mg/kg) may be used. In the case of acne urticata and moderate papulopustular adolescent acne, low-dose treatment with isotretinoin (0.3—0.4 mg/kg) is advisable, the duration of the course is up to 1 year. Various regimens of isotretinoin in patients with severe to moderate acne are safe and well tolerated. Adverse effects on the skin and mucous membranes are quite common, but they are transient (the severity significantly reduces over time), respond to moisturizing topical therapy and do not necessitate discontinuation of therapy.