Tylosin is a macrolide antibiotic. It impedes protein synthesis in the microorganism cell by an effect on translocation; binding to the 50S subunit of ribosome. Leads to functional disturbances with blockage of certain stages in the protein synthesis (RNAt-fenil-alanina with ribosomal function), resulting in the death of bacteria. The drug may be bactericidal or bacteriostatic, the effect depending on its concentration and on the type of the microorganism, which is bacteriostatic at normal dose and bactericidal at high dose. Tylosin is a drug of choice as an alternative to penicillin in infections with Streptococci, corynebacterias, mycoplasmas, Chlamydia and legionella, especially in infections of respiratory tract.