Periapical abscesses are common but may rarely be a subclinical infection in dental clinics. If an infection progresses rapidly or slowly as a tooth ache of chronic periodontitis with clinical features misleading the diagnosis, the dentists are able to recognize the salient signs and identify the patients at risk. This article reviews a case of a rare innocuous periapical abscess presenting as angioedema of upper lip with history of consuming nonsteroidal anti-inflammatory drugs such as diclofenac sodium whenever needed for arthralgia on a short-term basis.