Micronutrients can inhibit oxidation reactions due to micro-organisms in human tissues. In this randomized, double-blind and placebo-controlled pilot study, it was examined whether suppletion of a mixture of selected micro - nutrients could affect the outcome of conservative treatment of periodontitis. A group of 16 for periodontitis treated patients received a mixture of micro - nutrients consisting of a-tocopherol acetate, ascorbic acid, cholecalcipherol and an extract from green tea, whereas a group of 16 similar patients received a placebo. At baseline and after 3 and 6 months, in every patient the number of teeth with periodontitis, the number of gingival bleedings on probing, and the pocket depths were registered. An evident improvement was defined as 40% reduction of the number of gingival bleedings on probing or of the summated pocket depth. After 6 months, the number of gingival bleedings on probing was significantly more reduced in the experimental group when compared with the placebo group. Also evident improvement was significantly more observed in the experimental group w hen compared with the placebo group.