That burning feeling in your chest after you eat a heavy meal could be heartburn. Or it could be worry over the drugs you\u2019ve taken to treat that heartburn. Among the top medical stories of 2019 was the discovery of contaminants in common medicines, and ranitidine\u2014best known as Zantac\u2014took up a large share of those headlines. A cancer-causing substance known as NDMA has been repeatedly found in one of the most popular antacid drugs in the United States.