Introduction: It is presumed that extrinsic afferent nerves link the rectum to the central nervous system. However, the anatomical / functional existence of such nerves has never previously been demonstrated in humans. Therefore, we aimed to identify and make electrophysiological recordings in vitro from extrinsic afferents, comparing human rectum to colon. Methods: Sections of normal rectum and colon were procured from anterior resection and right hemicolectomy specimens, respectively. Sections were pinned and extrinsic nerves dissected. Extracellular visceral afferent nerve activity was recorded. Neuronal responses to chemical (capsaicin and 'inflammatory soup' [IS]) and mechanical (Von Frey probing) stimuli were recorded and quantified as peak firing rate [range] in one-second intervals. Results: 28 separate nerve trunks from 8 rectums were studied. Of these, spontaneous multi-unit afferent activity was recorded in 24 nerves. Peak firing rates increased significantly following capsaicin (median 6 [range 3-25] spikes/sec vs. 2 [1-4], P<0.001) and IS (median 5 [range 2-18] spikes/sec vs. 2 [1-4], P<0.001). Mechanosensitive 'hot-spots' were identified in 16 nerves (median threshold 2.0g [range 1.4-6.0g]). In 8 of these, the threshold decreased after IS (1.0g [0.4-1.4g]). By comparison, spontaneous activity was recorded in only 3/30 nerves studied from 10 colons and only one 'hot-spot' (threshold 60g) was identified. Conclusions: This study confirms the anatomical / functional existence of extrinsic rectal afferent nerves and characterizes their chemo- and mechano-sensitivity for the first time in Man. They have different electrophysiological properties to colonic afferents and warrant further investigation in disease states.