Introduction. Today, antibiotics, uroseptics, diuretics, antispasmodics, etc. are widely used in the treatment of urological diseases. However, the use of herbal remedies occupies a special place, since herbal remedies act comprehensively and rarely cause undesirable reactions of the body. Based on the above, the author is Mullajonova M.T. a diuretic collection (DC) was developed, containing 2 parts dog rose hips, 1 part black currant leaves, 1 part lemon balm leaves. Objective: was to study the diuretic activity of DC, as well as assess the synergy of the components of DC. Material and methods. The study of diuretic activity was carried out according to the generally accepted method on a model with water loading. As a reference drug for assessing specific activity, we chose a reference diuretic preparation containing: solution – 100 g: active components: 29 g of aqueous-alcoholic extract from 1,8 g of a mixture of medicinal plant raw materials (1:1:1): centaury herb, lovage roots, rosemary leaves; excipients: purified water – 71,0 g; ethanol content: 16,0–19,5% (v/v) Results. Based on the results of the study, it was found that the test preparation has reliable diuretic activity, which is comparable to the reference diuretic preparation. It was also found that the test preparation reliably exceeded the diuretic activity of the individual components included in the test preparation/DC, which proves the synergy of DC. A range of effective doses has also been established and a dose of 1000 mg/kg is recommended as the most effective. Conclusion. The studied DC has reliable diuretic activity comparable to the reference diuretic preparation, and the synergism of the DC components has also been proven. The range of effective doses was also studied and the most effective dose was determined.