We evaluated the efficiency of 5 months Diavit treatment (blueberry and sea buckthorn extract) in diabetic children, compared to 2 months of Diavit and placebo. We studied 25 children, aged 12,4 ± 3,34 (SD) years. After 2 months of Diavit the mean value of glycated hemoglobin was diminished (9,77 ± 2,61%) compared to 10,99 ± 2,25% at the beginning of the study (p<0,05). After 5 months of Diavit treatment we obtained the mean value of 8,99 ±2,56% (p<0,05). Mean insulin doses decreased from 0,96 ± 0,27 IU/kgbodyweight to 0,89 ± 0,28 after 2 months of Diavit (p<0,05), we could reduce insulin doses in 66,7% of the patients, and after 5 months the average dose was 0,87 ± 0,28 (p<0,05), 72,2% of the children needed lower doses. We can conclude that Diavit associated to insulin has a benefic metabolic effect in diabetic children, especially long term treatments.