The invention relates to a laser system (1), comprising a laser source (3) for generating a laser beam (4) and a control unit (5). A wave length (λ) of the laser beam (4) is in a range from above 1,9 µm to 11,0 µm inclusive. The laser system (1) including the control unit (5) is adapted for a thermal, non ablative treatment of mucosa tissue (2) by means of the laser beam (4) such, that the laser source (3) generates the laser beam (4) in single pulses (p) with a pulse duration (tp) in a range from 1,0 µs, inclusive, to 1,0 sec, inclusive. A fluence (F) of a single pulse (p) of the laser beam (4) on a target area (6) of the mucosa tissue (2) is in a range from 0,2 J/cm2, inclusive, to 2,0 J/cm2, inclusive, and preferably in a range from 1,0 J/cm2, inclusive, to 1,9 J/cm2, inclusive.
