Drug-induced disease is a common clinical entity. Drug-inducing anaphylaxis is a serious adverse effect. Several cases of allergic acute coronary syndrome or Kounis syndrome were reported. Premature ventricular contractions are the most frequent cardiac arrhythmia with or without structural heart diseases. A premature ventricular contraction is a sign of decreased oxygenation to the myocardium and anxiety but is also found in a healthy heart. A middle-aged married male patient presented to the physician outpatient clinic with syncope within one hour after ingested one tablet of diclofenac potassium (50mg). Diclofenac potassium-induced anaphylaxis and Kounis type I syndrome with premature ventricular contractions. Electrocardiography, oxygenation, monitoring for vital signs, and echocardiography were the done interventions. The dramatic disappearance of anaphylactic shock, Kounis type I syndrome, coronary artery spasm, and premature ventricular contractions after the traditional treatment of anaphylaxis had happened. Complete clinical and electrocardiographic recovery had achieved. The identiication of drug-induced disease is a pivotal step in the diagnosis decision making of any medical problems. Diclofenac potassium can induce anaphylactic shock, Kounis type I syndrome, coronary artery spasm, and premature ventricular contractions. Kounis type I syndrome, coronary artery spasm, and premature ventricular contractions can be reversed with treatment of the cause without using anti-ischemic or ant-arrhythmic measures. Reassurance was the recommended regards diclofenac potassium-induced both coronary artery spasm and premature ventricular contractions that accompanied by anaphylaxis.