Introduction: Environmental pollution with heavy metals, dioxins and PCBs is a serious ecological and health problem, as they enter our bodies with the food we consume. Metals and dioxins can bioaccumulate and biomagnify, thus theoretically lower levels of toxins in the body should characterize individuals using a vegan diet that excludes products of animal origin. Methods: The contents of heavy metals: arsenic (As), barium (Ba), chromium (Cr), zinc (Zn), cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb) and mercury (Hg) as well as dioxins and polychlorinated biphenyls (PCBs) was analyzed in the breast milk of 50 women in relation to the type of diet they ate (traditional Polish or excluding meat). The concentration of metals in breast milk was determined with mass spectrometry, whereas the concentration of dioxins and PCBs was determined using gas chromatography. Results: It was found that in some breast milk samples the content of arsenic, barium, chromium, nickel, lead and mercury exceeded admissible concentrations. Higher concentrations of copper and barium were determined in samples from women using the traditional diet, while in breast milk from women on a vegetable diet there was a higher concentration of mercury and nickel. Higher levels of heavy metals were found in breast milk samples collected in spring than in autumn. The concentration of dioxins and polychlorinated biphenyls did not exceed admissible values. Conclusions: The ambiguous influence of the diet type on toxin concentration in human milk was observed. It cannot be stated unequivocally that vegetarian diet is a preventive factor against the accumulation of heavy metals or dioxins and PCBs in human milk.