Stomach cramps increased; Upset stomach; Memory is not good/sometimes she remember things that amazes her and sometimes she cannot remember what happened yesterday; Pain in lower abdomen; This is a spontaneous report from a contactable consumer (patient) and physician. A female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: solution for injection, Batch/Lot Number: EW0167), dose 2 via an unspecified route of administration, administered in Arm Left on 29Apr2021 12:00  as 2nd dose, single dose for COVID-19 immunization; palbociclib (IBRANCE), via an unspecified route of administration from Apr2016 (Batch/Lot number was not reported) to 27May2021, at 125mg caplets oral with water for 21 days on and seven days off once a day for stage IV metastatic breast cancer. The patient's medical history and concomitant medications were not reported. No patient history. Family Medical History Relevant to AE(s): None. No other products. History of all previous immunization with the Pfizer vaccine considered as suspect: None. Prior to the vaccination, the patient was not diagnosed with COVID-19. Since the vaccination, the patient had not been tested for COVID-19. The patient did not receive any other vaccines within four weeks prior to the vaccination. The patient previously took BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, formulation: solution for injection, Batch/Lot Number: EW0153), dose 1 via an unspecified route of administration, administered in Arm Left on an unspecified date 12:05 as 1st dose, single dose for COVID-19 immunization and had stomach cramps. The patient stated that she was on Ibrance. The patient stated that she had second shot on 29Apr2021. Since the second vaccine, she had so much trouble with her stomach. The patient stated that this had been an ongoing thing. Her stomach cramps increased, and she had pain in her lower abdomen. The patient stated that she had the first shot three weeks before the second shot and had stomach cramps. The patient stated that stomach would not settle down. The patient stated that she would get some good days. The patient stated that last week on Thursday that she was in downward spiral and could not get out of it. The patient stated that she was being careful with what she ate. The patient stated that she stopped the Ibrance. The patient stated that this week was her seven days off and she would call today to ask for next month but wanted to take a reduced amount. The patient stated that when she saw her oncologist that she asked if people ever stop taking Ibrance and was told no that if one has a reoccurrence that it may not work as well. The patient stated that she did not ask for a reduction at that time but intends to. It was a temporary stop. The patient stated that this was more about Ibrance than the vaccine. The patient stated that she had pain in lower abdomen that started 10 days ago. The patient stated that she gets upset stomach from time to time but that it had been pretty constant since the first week in May. The patient stated that sometimes she remembers things that amazes her and sometimes she cannot remember what happened yesterday. The patient stated that other factors were involved (memory) at that time that her husband was ill. The patient stated that the stomach cramps started again 6 days after second vaccination and resolved last week. Recovered with lasting effects of upset stomach. The patient stated that she changed from capsules to caplets in 2020. The patient was treated with Mylanta. The patient stated that she had a video call scheduled with her nurse practitioner. Is eating soft foods and keeps drinking water. Relevant Tests: None. The event did not result in Emergency Room/Physician Office. The outcome of the events stomach cramps increased was recovered with sequelae, pain in lower abdomen, upset stomach was recovered, memory is not good/sometimes she remember things that amazes her and sometimes she cannot remember what happened yesterday was unknown.  Follow-up attempts are possible. Further information is expected.