An endoscopic bite block (30), comprising: a central channel (36) comprising an upper wall having an upper outer surface (32) and an upper inner surface； and a lower wall having a lower outer surface (34) and a lower inner surface； a breath sampling channel (62) configured to sample orally exhaled breath； a front plate (42) merged with an outer end section of said central channel, said front plate comprising an upper section and a lower section； said upper section comprising a groove (72), and a collection tube (60) connectable to said breath sampling channel, said collection tube configured to receive the orally exhaled breath sampled by said breath sampling channel.
