Nowadays, food and medicine are two key elements in treatment and prevention of diseases. It is necessary to pay attention to food and drug interactions in order to create ideal conditions for drug effects and provide normal nutritional status to prevent unwanted interactions between food and drug. This study aimed to investigate the range of observing standards of food and drug interactions in hospitalized patients. This study was conducted on 400 hospitalized patients. Data gathering tool included a checklist comprising two sections one of which was used to list demographic data and the other one to record food and drug interaction of 19 commonly prescribed medications using inquiries. According to data from participants who had to take medicine with full stomach, the following interactions were observed: Among the 19 widely consumed medicine in the internal hospital ward, only 2 (10%) were used completely according to the instructions for use of the medication on given meal (magnesium hydroxide and salicylic acid) and in relation to other medications, a maximum of 72.1% matching was observed (omeprazole). Based on the findings of this study, following the guidelines for timely medication administration was not met in the hospitalized patients. To strengthen adherence to food-drug interactions guidelines and make alliance between health care providers and the establishment of regular team, ongoing education of health professionals is recommended.