The aim of this study was to investigate the effect of various chemical and natural substances that were added to the boar semen extender as a substitute for antibiotics on the inhibition of microorganisms and their influence on the survival of the sperm. Tested substances Salicylic acid (KSA A – 0.015 g / l, KSA B – 0.03 g / l and KSA C – 0.15 g / l), sorbic acid (KS A – 0.015 g / l, KS B – 0.03 g / l and KS C – 0.15 g / l), benzoic acid (KB A – 0.34 g / l, KB B – 0.5 g / l and KB C – 0.66 g / l) and propolis (P 50 µl / l) were added to the boar semen extender to put BTS without antibiotic (BTS0). The survival of the sperm was due to the storage time and affects the dilution ratio (p 0.05) not found. In summary, let’s say that the use of the tested substances as potential substitutes for antibiotics in boar semen extenders is not entirely possible, but these substances could reduce the dose of antibiotics used in the extender as they reduce the antibacterial activity of microorganisms. The decrease in sperm survival was not found for these substances in comparison to the control sample. It is therefore necessary to research other potential substances as a possible substitute for antibiotics in boar semen diluents.