my stomach got very upset; nauseated; bad diarrhea on and off for hours; fatigued; lethargic; slept most of the day on Friday (after signing off of work) and I slept until almost noon both Sat and Sun; This is a spontaneous report received from a contactable reporter(s) (Consumer or other non HCP). The reporter is the patient.  A 45 year-old female patient (not pregnant) received bnt162b2 (BNT162B2), administered in arm left, administration date 08Apr2021 15:00 (Lot number: ER8737) at the age of 45 years as dose 1, single for covid-19 immunisation. Relevant medical history included: "IBS" (unspecified if ongoing); "obesity" (unspecified if ongoing); "chronic low back pain issues" (unspecified if ongoing); "chronic low back pain issues" (unspecified if ongoing); "chronic nasal allergies" (unspecified if ongoing); "anxiety" (unspecified if ongoing); "depression" (unspecified if ongoing); "melanoma" (unspecified if ongoing), notes: I have had melanoma more times than I can count.; "basal cell carcinoma" (unspecified if ongoing), notes: basal cell carcinoma once.; "bandage adhesive" (unspecified if ongoing), notes: Known allergies: only allergic to Vicodin and bandage adhesive.; "sensitive stomach, especially when I consume dairy products" (unspecified if ongoing), notes: I do have a very sensitive stomach, especially when I consume dairy products; "sensitive stomach, especially when I consume dairy products" (unspecified if ongoing), notes: I do have a very sensitive stomach, especially when I consume dairy products. Concomitant medication(s) included: CLARITIN-D; CYMBALTA. Past drug history included: Vicodin, reaction(s): "allergic", notes: Known allergies: only allergic to Vicodin and bandage adhesive. The following information was reported: ABDOMINAL DISCOMFORT (non-serious) with onset 09Apr2021 08:00, outcome "recovered" (2021), described as "my stomach got very upset"; NAUSEA (non-serious) with onset 09Apr2021 08:00, outcome "recovered" (2021), described as "nauseated"; DIARRHOEA (non-serious) with onset 09Apr2021 08:00, outcome "recovered" (2021), described as "bad diarrhea on and off for hours"; FATIGUE (non-serious) with onset 09Apr2021 08:00, outcome "recovered" (2021), described as "fatigued"; LETHARGY (non-serious) with onset 09Apr2021 08:00, outcome "recovered" (2021), described as "lethargic"; SOMNOLENCE (non-serious) with onset 09Apr2021 08:00, outcome "recovered" (2021), described as "slept most of the day on Friday (after signing off of work) and I slept until almost noon both Sat and Sun". Therapeutic measures were not taken as a result of abdominal discomfort, nausea, diarrhoea, fatigue, lethargy, somnolence.  Additional information: Facility type vaccine was Pharmacy or Drug Store. It was reported that, About 18 hours after the shot (so on Friday morning around 8 AM PST), her stomach got very upset and she got nauseated and had bad diarrhea on and off for hours. She also became quite fatigued and lethargic and slept most of the day on Friday (after signing off of work) and she slept until almost noon both Sat and Sun (after feeding the dogs in the morning). As of Monday, she felt much better.Prior to vaccination, the patient wasn't diagnosed with COVID-19. Since the vaccination, the patient hasn't been tested for COVID-19. Patient didn't receive any other vaccines within 4 weeks prior to the COVID vaccine.  No follow-up attempts are possible. No further information is expected.