Seizure aggravation by antiepileptic drugs (AEDs) is an overestimated phenomenon. While it undoubtedly occurs, the quality of evidence in most published reports is poor. Although seizure aggravation can be examined in clinical trials in the same way as seizure improvement, this is rarely done. Before concluding that an increase in seizures after the introduction of a new drug represents pharmacodynamic aggravation, alternative explanations should be explored. These include spontaneous fluctuation of seizure frequency, the presence of known seizure aggravators (such as sleep deprivation, alcohol, and psychotropic medications), progression of epilepsy, the development of drug resistance, and replacement of a partially effective drug with a less effective drug. The risk of incorrectly blaming a drug for a deterioration in seizures can be minimized by establishing baseline seizure frequency over a period long enough to encompass the extremes of seizure fluctuation and by educating the patient that a temporal relationship may not be a causal relationship. When feasible, the patient should continue the drug long enough to establish if the deterioration is transient. If the drug is stopped, rechallenge should be considered. The risk of seizure aggravation can be minimized by accurate diagnosis of the epilepsy syndrome and appropriate choice of AED.