Dentists handle drugs which can cause an overdose. Such are local anesthetics, vasoconstrictors, sedatives, and opioid analgesics. If the amount of a drug in aimed organs and tissues surpasses the therapeutic one, the clinical manifestations of an overdose begin. The clinical manifestation lasts for as long the blood level of the drug – is above the overdose threshold. Drug overdose in a dental office is an event where the dentist has to be ready to react quickly. The occurrence of an overdose reaction is affected by drug-related factors and the patient’s condition. To avoid it, the therapist uses the minimal quantity of the drug that provides a therapeutic effect. The incidence of an overdose reaction can be significantly decreased by analyzing the patient's medical history, doing a detailed clinical examination, and using the correct quantity of the drug. If an overdose reaction still occurs, the dentist follows a protocol of reaction to treat a specific kind of a drug overdose and provides the necessary therapy. The dentist decides if an ambulance should be called, based on his own aptitude, severity of the clinical manifestations and the equipment available in the dental office. Usage of the earlier mentioned drugs is inevitable in the everyday work of a dentist, as is the possibility of an onset of an overdose or a toxic reaction, which is why a dentist should conscientiously handle such drugs and be able to quickly recognize the symptoms of an overdose and how to react to them.