Pharmacovigilance aims to guarantee the safe use of medicines. It is based on the reporting of adverse effects by health professionals, industry and the public. Pharmacovigilance is the monitoring of drugs and the prevention of the risk of adverse effects resulting from their use, whether this risk is potential or proven. It relies on the spontaneous reporting of adverse events by health professionals and patients, the collection of adverse effects for the detection of signals the establishment of preventive measures. One such adverse drug reaction is calcium deficiency due to reduced calcium absorption caused by an important group of medication namely, proton pump inhibitors. The data of the following three patients were evaluated and causality assessment further established a “probable” relationship between the drug intake and time of administration.