<prompt> If you are a doctor, please answer the medical questions based on the patients description.I was recently diagnosed with an insectspider bite on my foot by a doctor in Italy. I am now in Greece on holiday. The only symptom is swelling and redness on the foot. Today, however, I discovered a lot of blood in my stool. I have no pain, no fever. Only slight discomfort and swelling in my foot  <response>: HI, thanks for using Chat Doctor The spider bite and the lesion on your foot should not cause blood in the stool, the two are not likely related. Blood in the stool can be due to different causes including : 1as a result of straining and constipation2 anal fissure, this however would normally be painful3hemorrhoids4diverticular disease5 benign polyp in the colon6cancer of the colon7infection8Crowns or ulcerative colitisExamination of the abdomen and anus, analysis of a stool specimen and imaging may be needed to identify a cause. I hope this helps 