A 55-year-old woman's teeth were whitened with a 35% hydrogen peroxide product. In the European Union, no tooth-whitening product sold as a cosmetic may contain more than 6%, and even that strength is reserved for dentists. Her doctors now suspect the whitening solution caused an airway blockage that collapsed part of her lung and looked like a tumor on her scans.
The case, published in Cureus in January 2026 by Redouene Sid Ahmed Benazzouz, Massinissa Benyagoub and Nassim Nedjar of Laghouat Public Hospital in Algeria, describes a North African cook and lifelong nonsmoker with no history of lung disease. Their report proposes that she inhaled vapors or tiny droplets of the whitening solution during the procedure.
