Allergic and pseudoallergic reactions can be associated with all drug classes used in dental practice. A thorough medical history is essential to avoid challenging a patient with an agent for which they have proven intolerance. Despite this precaution, the dentist must be prepared to manage an immediate reaction, should it occur. In all cases, management should begin with standard ABC assessment and oxygen supplementation. The administration of either diphenhydramine or epinephrine is predicated on the severity of the reaction. Suggestions regarding dosages and routes of administration are summarized in Table 4. The duration of action for epinephrine is relatively brief (10 to 30 minutes), and dosages may need to be repeated if symptoms recur. Following stabilization, patients who have experienced anaphylactoid reactions should be transported by EMS to the closest emergency room for definitive management. A treatment algorithm summarizing management of allergic reactions is presented in Figure 1.