Applications of lasers in medicine for diagnostical and surgical purposes were spreading in the last decade. Surgical use of medical lasers can cause pyrolysis products as gases, vapours and fine particles or aerosols evaporating from the surgical theatre. Risk assessment to humans exposed to these potentially toxic agents needs a comprehensive analytical approach for characterizing these complex mixtures. In the respirable volatile organic compounds (VOC) fraction of laser treated model organs, besides a wide range of pyrolytic fragmentation and Maillard reaction products, two new classes of compounds, 2,4 dialkyl-2H-pyrrole 3,5 (3H) diones and 3-alkenyl-5-alkyl-pyrrolidine 2,4 diones, could be detected. According to our present knowledge, about 35 possible compounds belong to two families of alkylalkenyl substituted diketopyrrolidines and dialkyl substituted diketopyrrolines (DKP). Formation of these compounds was first detected by Curie-point pyrolysis of protein-containing organic matter. Special sources of these VOC may be paired aliphatic amino acids in peptides. Laser-tissue interaction along with (poly-)amino acids with alkyl substituents will be a favourable source of these new volatile organics.