The symptoms of acid-dependent diseases (ADD) not infrequently complicate the normal course of pregnancy especially in the women presenting with gastroesophageal reflux disease (GERD) who suffer from severe heartburn or belching. The numerous evidence-based studies have demonstrated that proton pump inhibitors (PPI) are the most efficient of the currently available medications for the management of GERD and other acid-dependent diseases. Therapy with the use of these medicines makes up the basis for their safe and reliable treatment, their application is recommended in all recently published guidelines for the diagnostics and treatment of these conditions. However, the clinical feasibility of PPI therapy during pregnancy remains a matter of debate. The present article is focused on the analysis of the results of the clinical studies and observations carried out to evaluate the safety of PPI prescribed to the patients presenting with GERD and other ADD. The special emphasis is placed on the use of omeprazole the safety of which has until recently been estimated only based on the results of administration of its large doses to the experimental animals. For this reason, the FDA experts referred omeprazole to category C. This issue is brought up for discussion in the present article taking into consideration that the instruction for use of omeprazole 20 mg (Omez 20 mg) contains the clearly-defined indications for its application by the pregnant and breast-feeding women.