Simple SummaryCampylobacter jejuniis considered the most common causative agent of human bacterial foodborne gastroenteritis worldwide with poultry products, and especially broilers meat, being the most common source. The aim of this study was to investigate the effect of the continuous application of three commercial water acidifiers (ProPhorce™ SA Exclusive, Premium acid, and Salgard®Liquid) on the performance, gut health, andC. jejunicolonization in experimentally challenged broiler chicks. The experimental findings demonstrated that acidification of the drinking water by the tested products did not affect the transmission ofC. jejunifrom the seeder to sentinel birds, under the conditions used in this study. However, all the products ameliorated the adverse effects induced byC. jejuniinfection in the physicochemical characteristics of the intestinal content. Finally, the continuous use of certain products from the first days of life evoked undesirable effects on broilers’ performance and induced severe gross lesions in the upper gastrointestinal tract, leading to the need to modify the dosage scheme in future investigations.AbstractThis study investigated the effect of three commercial water acidifiers on the performance, gut health, andC. jejunicolonization in experimentally challenged broiler chicks. A total of 192 one-day-old broiler chicks (Ross 308®) were randomly allocated into 6 treatment groups with 4 replicates according to the following experimental design: group A, birds were not challenged and received tap water; group B, birds were challenged and received tap water; groups C, D, E, and F, birds were challenged and received tap water treated with 0.1%v/vSPECTRON®, with 0.1–0.2%v/vProPhorce™ SA Exclusive, with 0.1–0.2%v/vPremium acid, and with 0.1–0.2%v/vSalgard®Liquid, respectively. The continuous water acidification evoked undesirable effects on broilers’ performance and to an increased number of birds with ulcers and erosions in the oral cavity and the upper esophageal area. ProPhorce™ SA Exclusive and Premium acid significantly reduced theC. jejunicounts in the crop, whereas Salgard®Liquid significantly reduced theC. jejunicounts in the ceca of birds. At slaughter age, only Premium acid significantly reducedC. jejunicounts in the ceca of birds. All the tested products ameliorated the changes induced byC. jejuniinfection in the pH in the ceca of birds. It can be concluded that besides the effectiveness of the tested products in controllingC. jejuniin broilers, their continuous application evoked undesirable effects on broilers’ performance, leading to the need to modify the dosage scheme in future investigations.