In the preantibiotic era, Ludwig's angina frequently caused asphyxiation and death. Recognized less often today, this rapidly progressive submaxillary cellulitis may still be fatal. A case associated with Haemophilus influenzae bacteremia in an adult is presented. Twelve additional cases of cellulitis of the neck in adults with H influenzae bacteremia are summarized. One hundred forty-one cases of Ludwig's angina reported since 1945 are reviewed and compared with 315 earlier cases. In the cases reported in the antibiotic era, the mean age of the patients was 29 years. Most patients were previously healthy but had evidence of dental disease. Submandibular swelling, elevation of the tongue, fever, dysphagia, and trismus were each present in more than one half of patients. Streptococci and anaerobes were most frequently isolated from soft-tissue cultures. Untreated, this illness is fatal in one half of patients. Early recognition is therefore essential. Appropriate therapy includes maintenance of the airway, antibiotics, and surgical drainage when indicated.