The anaerobic treatment system is a promising alternative for pharmaceutical wastewater treatment. This report is a case study of a laboratory investigation into the treatment of pharmaceutical wastewater containing the antibiotic Tylosin in an anaerobic reactor. Specifically, the research sought to determine whether the anaerobic reactor could be used as a pre-treatment system at an existing pharmaceutical production plant. The reactor showed efficient substrate removal at low organic loading rates by promoting efficient chemical oxygen demand reduction. Under these conditions, an average of 95% Tylosin reduction was achieved in the up-flow anaerobic stage reactor. However, changes in the organic load reduced removal efficiency.