acute diarrhea and it had been 16 days and it had not stopped. She has been going 7 to 10 times a day; Being dehydrated from having so many bowel movements; slight fever of 99.7 every night/She was still at 99.6, 99.7 so for the first few days it was over a 100/99 was a fever for her; Little bit of headache; ears got kind of hot; This is a spontaneous report from a contactable consumer (patient).  A 48-year-old female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, solution for injection) (at 48 years of age), via an unspecified route of administration, administered in arm left on 19Apr2021 (Batch/Lot Number: ER8737) as 2ND DOSE, SINGLE for COVID-19 immunisation. Medical history included ongoing herpes simplex that has been going for years. Concomitant medication included aciclovir (ACYLO [ACICLOVIR]) taken for herpes simplex from an unspecified start date and ongoing. Historical vaccine included BNT162B2 dose 1 (Batch/Lot Number: ER8732) on 29Mar2021 in the left arm for COVID-19 immunisation. The patient got her second Pfizer vaccine on April 19th as soon as she got her shot, her ears got kind of hot and then she has had acute diarrhea and it had been 16 days and it had not stopped. She has been going 7 to 10 times a day. She was still running a slight fever of 99.7 every night and her doctor was, they have been trying everything they can to stop the diarrhea. Just a little bit of headache but she does not know if the headaches are from being dehydrated from having so many bowel movements, so with the headaches, so they cannot stop it. Her doctors have her on three medications, one of them was an antibiotic, one of them was Imodium (later confirmed as loperamide) just a few things and the other one was a muscle contractor in the GI tract trying to stop her muscles from spasming and he tested her for every parasite, every bacterial, everything, did a CAT scan, everything was coming back negative. She confirmed that she got the symptoms the very next day, so 20Apr2021 was the day that she started all her symptoms. So, still current. She was still at 99.6, 99.7 so for the first few days it was over a 100, so it did go down after the first 2 days but then after that it just stayed at 99. She mentioned that her temp usually runs at 96, so 99 was a fever for her. She added that she went to the hospital 2 times. In 2 different times because she got IV fluid. The first one was on 23Apr2021, the second time she went was on 03May2021. She confirmed that she went to the hospital for treatment and no hospitalization was done. She added that she was treated then was released, she was given fluid through an IV and then they released her, because all the diarrhea was making her dehydrated because she was losing so much. She did not get admitted, she just went in and was treated and released. She was tested for bacterial, parasite, HIV, Hep C, gonorrhea, chlamydia, STD everything. Everything they tested her was coming back negative. They also did CAT scan, they have done everything, but cannot figure out why the diarrhea won't stop, they have put her on all those stuffs, and nothing was working. She asked what she should do to stop the diarrhea. Therapeutic measures were taken as a result of the events. For diarrhea she was given antibiotic Vancomycin 250 mg three times a day for 10 day from 29Apr2021 and was still using; loperamide 2 mg four times a day from 23Apr2021 and was still using; and the next one was just put her on because she had to go back to the hospital the other day was dicyclomine 20 mg, four times a day from 3May2021 and ongoing. She was also given with Benadryl through an IV at the hospital and they also gave her a medicine to stop that 'poison reaction' (not clarified further), and then they have her scheduled with a GI specialist too. There was another name of the medicine that they treated her at the hospital, they said she was having a reaction, so they gave her atropine and then they put Benadryl, they gave her that at the ER on 23Apr2021. Also, they give her a COVID test and that was negative too at the hospital on the 23Apr2021. The outcome of the events was not recovered.  Information about Batch/Lot number available. Additional information has been requested.