As the imported fire ant relentlessly expands its territory, more and more people are at risk of the insects' discomforting and sometimes dangerous stings. Thus, all primary care physicians in fire ant-infested areas should be familiar with diagnosis and treatment of fire ant stings and of allergic reactions to the stings. Fire ant venom is unique when compared with other Hymenoptera venoms, as it consists mainly of nonallergenic alkaloids that are of small molecular weight with only a small percentage of allergenic proteins. Fire ant wholebody extract, unlike other Hymenoptera wholebody extracts, retains its allergenic activity and is an adequate material for use in diagnostic testing and immunotherapy. Diagnosis of fire ant allergy can be readily made by the radioallergosorbent test (RAST) or by skin testing using fire ant wholebody extract. Immunotherapy with fire ant whole-body extract in allergic individuals can prevent serious recurrent systemic reactions.