My dissertation s main goal is , to talk initially about the general use of antibiotics in dentistry for example antibiotic recommendations, are based on two categories of infections localized: pain in tooth, infection visible on radiograph, only slight swelling and spreading: swelling closing eye, swollen naso-labial fold, pronounced intra-oral swelling.Later on this thesis analyzes the properties of Penicillins and Lincosamides in general, including briefly information about their structures,their clasiffication, mechanisms of action, drug resistances and drug interactions