I was admitted with a GI bleed and was hospitalized; bloody bowel movement; Severe anemia from loss of blood; This is a spontaneous report from a contactable consumer (patient). The 58-years-old male patient received bnt162b2, dose 1 via an unspecified route of administration, administered in Arm Right on 04May2021 16:08 (Lot Number: EW0169) as SINGLE DOSE for covid-19 immunisation at the age of 58 years old. Medical history included ongoing type 2 diabetes mellitus, Caller reported that he was diagnosed with type 2 diabetes about 5 years ago , ongoing High blood pressure, Caller reported that he was diagnosed with high blood pressure a little over 5 years ago. The report was not related to a study or programme. Family Medical History Relevant to AE(s) was None. Concomitant medication included Metformin began 5 years ago and ongoing for diabetes, Lisinopril began 5-6 years ago and ongoing for High blood pressure, empagliflozin (Jardiance) from about a year ago and ongoing for diabetes. No additional Vaccines Administered on Same Date of the Pfizer Suspect. The patient previously took flu shot for immunisation and experienced Just regular arm soreness at shot site. Caller reported that he experiences a sore arm at the injection site each year with the flu shot. No Prior Vaccinations (within 4 weeks). The patient experienced i was admitted with a gi bleed and was hospitalized on 11May2021 22:30 with, severe anemia from loss of blood on May2021. Reported as: I got my first dose on 04May and on 12May I was admitted with a GI bleed and was hospitalized until the 29th. They could not find a source of the bleed and no one could tell me if it was related to the vaccine. The GI bleed was onset on 11May2021 22:30, and the patient admitted for the event from 12May2021 to 29May2021. Caller reported that he was bleeding and was admitted to the hospital. Caller reported that he spent 19 days in the hospital and the medical staff never found where the GI bleed was coming from. Caller reported that he asked doctors from each department if the GI bleed had to do with the Covid-19 vaccine. Caller reported that all of the physicians told him that they had not heard of that yet. Caller reported that he just got off the phone with his company RN who suggested that he call Pfizer to report the incident. Caller reported that he was scheduled to get the second dose of the Covid-19 vaccine on 24May2021. Caller reported that he cancelled the appointment because he was in the hospital. GI bleed: Caller reported that the GI bleed started at his place of work at 10:30 PM on 11May2021. Caller reported that the GI bleed has quit at this point, but they could never determine what caused the bleed or where it was coming from. Caller reported that he had to have several blood transfusions while he was hospitalized. Caller reported that the GI bleed started 1 week after he got his first dose of the Pfizer Covid-19 vaccine. Caller reported that none of his physicians would confirm or deny that his GI bleed was related to the Covid-19 vaccine. Caller reported that his last bloody bowel movement was on the morning of 29May2021. Investigations: Caller reported that while he was hospitalized, medical staff did a colonoscopy, upper GI scope, radiology, interventional radiology twice, CT scans, red blood cell traces through nuclear med, and gave him camera pill. Caller reported that the medical staff did an amazing amount of tests and never found where the GI bleed was coming from. The AE GI bleed required a visit to Emergency Room. The patient experienced Severe anemia from loss of blood in May2021. The outcome of the events was unknown.  Information on the lot/batch number has been requested