The aim of the present study was to investigate the effect of Probiotics in Progress (PIP) on the establishment of a competitive flora as well as on antibiotic use and losses of suckling piglets in pig breeding farms. The tested products were PIP AHC® and PIP AHS® produced by “Chrisal AG” in Lommel, Belgium. PIP`s are cleaning products containing Bacillus spores. According to the manufacturer‘s specifications, they are able to establish a steady non-pathogenic stable flora. In a field trial in 19 pig breeding farms, the use of PIP-products did not lead to any reduction of antibiotic use or improvement of fertility parameters, especially in relation to losses of suckling piglets. In addition, we compared the bacterial flora using PIP products with the flora under conventional management conditions in a farrowing pen by means of swab samples. The use of PIP-products did not lead to any significant effect on the pen flora. Only very few swab samples contained a majority of probiotic Bacillus spp.