In this paper, we propose a new feature for finding lesions in gastrointestinal tissues. Polyps or cancerous parts have different capillary pattern compared with normal parts. There are polyps which have higher density of vessel or capillary pattern. This feature leads us to extract remote photoplethysmogram signal from different parts of videos from gastrointestinal tissue. Due to the fact that hemoglobin absorbs more light than surrounding tissues, more changes are expected to be observed in the parts with higher density of vessels and capillaries. In the experimental results, rPPG signals is extracted from colonoscopy and endoscopy videos. This feature is used to distinguish between normal and abnormal tissues. It is shown that power of rPPG signal can be used to find lesion areas.