This thesis aims to describe the action of p-hydroxybenzoic acid esters as preservatives added to various pharmaceutical forms and cosmetic products. Their use enables them to achieve an appropriate shelf life by suppressing the growth of harmful microorganisms. In addition to chemical stability and a good antimicrobial effect, parabens show a minimal effect on the skin microbiome. They are most represented in pharmaceutical dosage forms and cosmetic preparations that are applied to the skin. The average daily intake of parabens in adults varies between 1 μg/kg from food and 0.833 mg/kg via cosmetic preparations for skin care, protection, cleansing and perfuming. As they are quickly metabolized into non-toxic metabolites, their use is considered safe. However, chronic use of paraben-preserved products can lead to their accumulation in tissues, however, the health risk arising from that is yet unknown. The estrogenic activity of parabens has been demonstrated in vitro, so it is suspected that they may contribute to the growth of oestrogen-dependent tumours. However, it must be noted that the estrogenic activity of parabens is 2.5 million to 10,000 times lower than that of physiologically present oestrogen. Furthermore, exposure to parabens in combination with ultraviolet radiation can induce the formation of reactive oxygen species in keratinocyte cell cultures, but in vivo this effect is questionable. By combining parabens with other substances, their amount in the preparation can be reduced, which leads to reduced exposure to parabens. Today, there is a growing awareness of the need to develop more effective methods for removing parabens from wastewater, to exclude their potentially unfavourable impact on the aquatic organism and the ecosystem in general.