When she went to the hospital for her stomach pain, the doctor told her she was dehydrated, and her small bowel had no water getting to it; She had a severe small bowel obstruction; She had a lot of stomach pain; Throwing up; she is ill/She is sick; She slept for most of the day the next day (after her first COVID-19 Vaccine dose); Flu-like symptoms; Headache; Her legs were hurting in the front (after her first COVID-19 Vaccine dose); This is a spontaneous report from a contactable consumer (patient) This consumer reported same event for 5 patients. This is the first of 5 reports.  This 65-year-old female consumer reported for herself that she received the first dose of BNT162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE, Lot Number: EW0158) on 20Apr2021 (at the age of 65-years-old) between 11:30 and 12:00 via an unspecified route in the left arm as a single dose for COVID-19 immunization. Medical history included small bowel obstruction, H. Pylori, acid reflux (esophageal), stomach problems with pains (ongoing), and doctor told her she was born with something that was stretched out on top of her stomach. She stated that her stomach pain comes and then goes away and that she has learned to work with her stomach pain. She said her doctor gave her some medicine that started with a "P" and it had worked really well. The patient also had a familial history of stomach cancer. Every year she had to go for an EGD and colonoscopy because of stomach cancer in her family. Her results have been so far, so good. There were no prior vaccinations received within 4 weeks of the COVID vaccine. There were no additional vaccines administered on the same date as the COVID vaccine. There were no concomitant medications. In Apr2021, after her first COVID-19 vaccine dose, the patient had flu-like symptoms which lasted for 2 days, headache, and her legs were hurting in the front. She also slept for most of the next day on 21Apr2021. She said the headache may have been her fault because she was told by the nurse who administered the COVID-19 vaccine to drink a lot of water. Patient stated she may have had the headache from being dehydrated. Treatment received for flu-like symptoms & headache included drank a lot of liquids and her headache went away. Patient didn't want to take Tylenol because she was afraid to. She said she walked herself through her flu-like symptoms for a few days. In two days she felt better. On 02May2021, she went to the emergency room because she had a lot of stomach pain. She was told she had a severe small bowel obstruction. Patient reported she started throwing up and had a tube put up her nose and down her throat. Patient added that she always had stomach problems with pain since she was a child, but "her heart didn't feel like take it could take the stomach pain", so she went to an urgent care. The urgent care sent her to the Emergency Room. Right when she got to the Emergency Room, she started throwing up. On 03May2021, she had major surgery where they went into her stomach with cameras and she had 3 dots made on her belly. She had the tube in her throat draining her stomach until 05May2021. She said when she went to the hospital (for her stomach pain), the doctor told her she was dehydrated and her small bowel had no water getting to it. She had the major surgery and can't drive. Her body was not up to par. The patient was hospitalized for severe small bowel obstruction, stomach pain, dehydrated, and throwing up from 02May2021 to 08May2021. It was also reported she had 4 more friends with flu-like symptoms. She clarified every woman she talked to about the COVID-19 vaccine all had the same type of symptoms after the first COVID-19 vaccine dose. Her brother and 2 male cousins had no symptoms after both doses of the Pfizer COVID-19 vaccine. Her doctor didn't want her to get the second COVID-19 vaccine dose until he sees her again. She said while she was in the hospital, she had asked the doctor and nurse to get the second COVID-19 vaccine, and both suggested that she wait on getting the second dose. Patient stated she can't get the second dose tomorrow (11May2021), because she states she is sick/ill. The clinical outcomes of flu-like symptoms, headache, and her legs were hurting in the front were recovered in Apr2021, while of small bowel obstruction, stomach pain, slept for most of the day the next day, throwing up, dehydrated, and sick/ill were unknown. The patient thought her stomach pain and small bowel obstruction had nothing to do with the COVID-19 vaccine.; Sender's Comments: The patient thought her stomach pain and small bowel obstruction had nothing to do with the COVID-19 vaccine.  The company consider all the serious events small bowel obstruction, stomach pain, dehydration, and vomiting were unrelated to the first dose of BNT162b2 (PFIZER-BIONTECH COVID-19 mRNA VACCINE).   The underlying small bowel obstruction, acid reflux (esophageal) and stomach problems with pains could explain the symptoms.  The case will be reassessed should additional information become available.  The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics committees and Investigators, as appropriate.,Linked Report(s) : US-PFIZER INC-2021531142 same reporter/SD/AE, different patient.;US-PFIZER INC-2021533619 same reporter/SD/AE, different patient.;US-PFIZER INC-2021533282 same reporter/SD/AE, different patient.;US-PFIZER INC-2021531607 same reporter/SD/AE, different patient.