Anaphylaxis is a rapid-onset, life-threatening, systemic hypersensitivity reaction that occurs in varying clinical and severities as a result of sudden mediator release from mast cells and basophils. Accurate estimation of the incidence of anaphylaxis is difficult due to difficulties in diagnosis, inadequacies in the recording system or inaccurate reporting. Foods (especially in children), medications and insect bites have been reported as the most common causes. During anaphylaxis, many different biochemical mediators, chemokines and cytokines are released as a result of the degranulation of mast cells and basophils. Some of these are mediators such as histamine, tryptase, heparin and carboxypeptidase, which are preformed in the granules within the cell; Some of them are newly produced platelet activating factor (PAF), prostaglandin (PG) D2, locotriene (LT) B4 and cysteinyl locotrienes (LTC4, LTD4, LTE4). The diagnosis of anaphylaxis is made with the help of history and physical examination using widely accepted clinical criteria. In anaphylaxis, there is usually involvement of at least two organ systems, but in some cases, involvement of only one organ system (hypotension in CVS) may be considered sufficient for diagnosis. It is vital that the first intervention and treatment be performed, if possible, at the place where the diagnosis was first made. The first drug that should be given in the treatment is adrenaline. Adult dose of adrenaline is 0.2-0.5 mg and the drug should be given intramuscularly (IM) to the front side of the thigh (vastus lateralis muscle). Before discharge, the patient should be evaluated in terms of the risk of recurrence of the reaction, and in addition to explaining other protective measures and recommendations in patients deemed to be at risk, an adrenaline auto-injector should be prescribed, and the patient and, if necessary, his/her relatives should be taught when and how to use it.