Experienced diarrhea; Weakness; Weight loss; This is a spontaneous report from a contactable consumer via Medical Information Team. A 71-year-old (a couple of weeks ago in the beginning of May) female patient received BNT162B2 (PFIZER-BIONTECH COVID-19 VACCINE, Solution for injection) via an unspecified route of administration on an unspecified date (Batch/Lot number was not reported, NDC number/Expiry Date: Unknown) (about 2.5 months ago but did not know her date of birth) as single dose for Covid-19 immunization. Caller stated she did not know the dates of the patient's 1st and 2nd doses of the Pfizer Covid Vaccine and did not have the lot numbers, expiry dates or NDC numbers to provide. The patient's medical history and concomitant medications were not reported. The patient previously took first dose of BNT162B2 (at the age of 71-year-old) for Covid-19 immunisation. The patient received both doses of vaccine. Experienced diarrhea, weakness (weaker and weaker) and weight loss. Caller stated steroids stopped it, side effects temporarily but she wanted to know what to do, how should the care for her or manage her side effects. Caller explained that she had seen several HCPs and they did not know what to do. Caller stated she was calling about the Pfizer Covid vaccine and stated her neighbour got this shot about 2.5 months ago and had diarrhea ever since and only weighed 90 pounds and was down to 82 pounds and she was calling to ask what to do; stated the patient's HCP could not figure out it and the patient was getting weaker and weaker. Caller stated the patient was not getting better and stated that Pfizer made the vaccine so they could tell her how to fix this problem and she did not know what to do and was trying to figure out what do to; stated the patient was in great health and walked miles every day and that bring her down; caller stated she told the patient did not to get the vaccine and the patient's daughter was out of Country so that she got it. HCP information: Caller declined to provide contact information for the HCP and stated she did not have that. Stated the patient began having diarrhea after the very first couple of days after the Pfizer COVID vaccine but she was not positive when it began and she was having the diarrhea so bad she had to wear diapers and it was ongoing and about the same but might be a little better because she learned to control it better and the patient was not eating anything to begin with and tried not to eat to not have an accident; stated the patient wakes up at night and realizes she had an accident with diarrhea in the morning. Caller stated the patient had no other treatment that she knows of and she was in very good health and had known the patient 21 years and always walked with her and walked every day she had known her and she rides her bicycle. Caller stated her questions are what they can do to stop the patient's reported events and she had been to the HCP more than once and tried everything and everything she tried did not work; stated she wants to see what junk they put in the Pfizer COVID vaccine. Caller was aware that Pfizer cannot provide treatment recommendations or medical advice and patient was referred to her HCP. Caller stated the patient went on steroids that worked for 5 days of the patient being on them and then the diarrhea came back and subsided and then came back; stated she had no names, dosages, lot numbers, expiry dates, NDC numbers or further information on the medications or treatments the patient stated did not work or for the steroids. No PQC present. Outcome of the events diarrhea was not recovered, whereas other events were unknown.  Information on the lot/batch number has been requested.