Had frank bloody, watery, mucousy stool; Had frank bloody, watery, mucousy stool; Had one episode of vomiting multiple times; Moderate abdominal cramping; Diarrhea; Dose Number: 3; This is a spontaneous report received from a contactable reporter(s) (Other HCP). The reporter is the patient.  A 28 year-old female patient (not pregnant) received bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE), administered in arm left, administration date 21Dec2021 16:00 (Lot number: 331308A) at the age of 28 years as dose 3 (booster), single for covid-19 immunisation. Relevant medical history included: "Known allergies: Tree nuts" (unspecified if ongoing); "Asthma" (unspecified if ongoing); "hx of SVT" (unspecified if ongoing); "Migraines" (unspecified if ongoing). Concomitant medication(s) included: SPIRONOLACTONE; MONTELUKAST; ESCITALOPRAM; and oral contraceptive pills (OCP). Past drug history included: Amoxicillin, reaction(s): "Known allergies"; Sertraline, reaction(s): "Known allergies". Vaccination history included: Bnt162b2 (Dose 2, Batch/Lot No: EK9231), administration date: 08Jan2021, when the patient was 27 years old, for COVID-19 immunization; Bnt162b2 (Dose 1, Batch/Lot No: EL0140), administration date: 18Dec2020, when the patient was 27 years old, for COVID-19 immunization. The patient did not receive any other vaccines within 4 weeks prior to the COVID vaccine. Prior to vaccination, the patient was not diagnosed with COVID-19. Since the vaccination, the patient been tested for COVID-19.  The following information was reported: IMMUNISATION (medically significant) with onset 21Dec2021 16:00, outcome "unknown", described as "Dose Number: 3"; HAEMATOCHEZIA (medically significant), MUCOUS STOOLS (non-serious) all with onset 22Dec2021 16:00, outcome "recovering" and all described as "Had frank bloody, watery, mucousy stool"; VOMITING (non-serious) with onset 22Dec2021 10:00, outcome "recovering", described as "Had one episode of vomiting multiple times"; ABDOMINAL PAIN (non-serious) with onset 22Dec2021 10:00, outcome "recovering", described as "Moderate abdominal cramping"; DIARRHOEA (non-serious) with onset 22Dec2021 10:00, outcome "recovering", described as "Diarrhea". The events "had frank bloody, watery, mucousy stool", "had one episode of vomiting multiple times", "moderate abdominal cramping", "diarrhea" and "had frank bloody, watery, mucousy stool" were evaluated at the emergency room visit. The patient described clinical course as follows: 10am on 22Dec2021, had one episode of vomiting multiple times, moderate abdominal cramping and diarrhea. She woke up later around 4pm on 22Dec2021 and had frank bloody, watery, mucousy stool with abdominal pain. Abdominal cramping and bloody stool was improving as of 24Dec2021 morning. Awaiting GI work-up. The patient underwent the following laboratory tests and procedures: sars-cov-2 test: (24Dec2021) unknown results, notes: Result Pending, Nasal Swab. Therapeutic measures were not taken as a result of haematochezia, vomiting, abdominal pain, diarrhoea, mucous stools.; Sender's Comments: The events were considered as intercurrent conditions and unrelated to product bnt162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE). This case will be reassessed upon receipt of follow-up information.