Diarrhea; feeling nausea; I didn't feel good today; my blood pressure was elevated; received four shot of the Pfizer by accident; This is a spontaneous report received from a contactable reporter(s) (Other HCP). The reporter is the patient.  A 65 year-old female patient received bnt162b2 (BNT162B2), administered in arm, administration date 29Nov2021 (Batch/Lot number: unknown) at the age of 65 years as dose 4 (booster), single for covid-19 immunisation. Relevant medical history included: "Hypertension" (unspecified if ongoing), notes: I have hypertension; "Back of my leg were hurting" (unspecified if ongoing), notes: I went to doctor because I am having the medical condition the back of my leg were hurting.; "I wasn't feeling well" (unspecified if ongoing), notes: I have went for something else because I wasn't feeling well. Concomitant medication(s) included: HCTZ taken for hypertension. Vaccination history included: Bnt162b2 (Dose: 01), administration date: Mar2021, for Covid-19 immunization; Bnt162b2 (Dose: 02), for Covid-19 immunization; Bnt162b2 (Dose: 03), administration date: Aug2021, for Covid-19 immunization. The following information was reported: INCORRECT DOSE ADMINISTERED (non-serious) with onset 29Nov2021, outcome "unknown", described as "received four shot of the Pfizer by accident"; DIARRHOEA (non-serious) with onset 30Nov2021, outcome "unknown", described as "Diarrhea"; NAUSEA (non-serious) with onset 30Nov2021, outcome "unknown", described as "feeling nausea"; MALAISE (non-serious) with onset 30Nov2021, outcome "unknown", described as "I didn't feel good today"; BLOOD PRESSURE INCREASED (non-serious) with onset 29Nov2021, outcome "unknown", described as "my blood pressure was elevated". Relevant laboratory tests and procedures are available in the appropriate section.  Additional information: Patient underwent for lab test Blood pressure elevated on 29Nov2021 and Blood work result was unknown on an unknown date. on Nurse stated, "I have received four shot of the Pfizer by accident I didn't have my card yesterday and I didn't realize that I have already received the booster back in March and yesterday when I show the doctor they asked me If I have gotten the booster shot and I have forgotten that I have receive the booster in march they gave me another booster shot and I am having the diarrhea now. "When paraphrased the concern, "The booster shot Right, I have went for something else because I wasn't feeling well, I was having pains in the back of my leg and my blood pressure was elevated and they asked me to if have got the booster shot and I forget that I had got it in march, because I got the first one back was in April and they gave me the other booster in march I didn't have my card and they I thought they were giving me the shot for something else I was thinking they were giving me the flu shot but they gave me booster shot when I came home I looked on the card I saw I have already got the COVID-19, the third shot in august they, they already gave me the booster shot so, I have gotten it four times but I am now having diarrhea."I am having diarrhea, I am having severe diarrhea otherwise I feel okay but then going to the bed I haven't anything eat today I didn't feel good today I didn't ate something this morning,I have been drinking coffee because I didn't feel so good yesterday because my leg hurting so, I took my medicine but I have been diarrhea from about 5' o clock since afternoon. Well no I have been just calling because I am having diarrhea from about may be 2 hours ago and I have been to vaccinate 4-5 times but it otherwise I just want make sure if it is okay?. "But I do have, I have hypertension my blood pressure was elevated yesterday and that is one of the reason I went. Anatomical site of administration: "On my right arm, they did it left or right, a left and then the right."Causality: "Well, I don't know if this is because of my blood pressure is up or because of the fourth shot or what because I tested, I didn't even realize that I had, I forgot about the third shot."Concomitant Medication: I take up the other medicine and I take medicines for my blood pressure and they change the medicine so they told me stop taking all the medicine that I was taking and they have now changed the medicine, "They do some blood work and I don't know what the blood work was because they do at the doctor's office." (further clarification unknown). Treatment: The only side effect I am having right now is from whatever shot that I got yesterday, I 'tested' I am having diarrhea and I am feeling nausea that's why I called."  No follow-up attempts are possible; information about lot/batch number cannot be obtained. No further information is expected.