Abstract: An adapter (1) for an exhaled breath measurement apparatus (2), comprising a first inlet (3) for tidal breathing, a second inlet (4) for air free from one or more component to be measured, through which and a first one-way valve (5) air flows when a test person inhales through the adapter (1) at the first inlet (3), and an outlet (6) for exhaled breath having a second one-way valve (7). A sample tubing (11) is positioned next to the first inlet (3) for tidal breathing for a continuous sample from the exhaled breath immediately inside the adapter (1), upstream the second one-way valve (7) at the outlet (6) for exhaled breath. An exhaled breath measurement apparatus (2) with such adapter (1). A method for measuring exhaled breath during tidal breathing by sampling continuously in an adapter (1) at a first inlet (3) into which a test person breathes, the sampling taking place upstream of an outlet (6) for exhaled breath.