The aim of the research: The aim of the research is to examine the potential cytotoxic effects of volatile compounds isolated from seeds of the plant species Lunaria annua on human carcinoma cells of breast (MDA-MB-231) and lungs (A549). The assumption is that after the exposure of carcinoma cells to volatile compounds their number will be reduced in comparison to the control group. Material and methods: The cytotoxicity was tested by the MTT method used to determine the percentage of metabolically active cells after exposure to Clevenger distillate, microwave extract, and Lunaria annua plant extract. Plant samples were prepared at five different concentrations (1 µg/mL, 5 µg/mL, 10 µg/mL, 50 µg/mL i 100 µg/mL), and the effect is seen after 4, 24, 48 and 72 hours. The efficacy of the extracts was observed spectrophotometrically after measurement of absorbance at 570 nm. Results: The results are graphically presented in relation to incubation times and the percentages of metabolically active cells. •In breast carcinoma cells, volatile compounds isolated from Lunaria annua seeds (Clevenger distillate, microwave extract and extract samples) have a better effect at higher concentrations, at different incubation times. The most significant effect on the reduction of metabolically active cells is achieved by microwave extract and extract samples at a concentration of 100 µg /mL after 72-hour incubation time. •In lung cancer cells, volatile compounds isolated from Lunaria annua seeds (microwave extract and extract samples) also have a better effect at higher concentrations, at different incubation times. In the Clevenger distillate sample, in the long run, each of the concentrations has approximately the same (constant) effect. The most significant effect on the reduction of metabolically active cells is achieved by the microwave extract and extract samples at the concentration of 100 µg/mL after 72-hour incubation time. Conclusion: In vitro exposure of human carcinoma cells of breast (MDA-MB-231) and lungs (A549) to volatile compounds isolated from seeds of the plant species Lunaria annua leads to reduced cell survival rate. Cytotoxic effects of volatile compounds depend on concentration and incubation time. Effect of isolated volatile compounds is not always proportional to the increase in concentration and incubation time and in some cases cell recovery occurs. The cytotoxic effect of volatile compounds isolated from Lunaria annua seeds is confirmed, which was the hypothesis of the research, and the next step is the confirmation of these effects by in vivo studies on the models of animal breast and lung cancers.