Any drug used to combat oesophageal reflux[?]. Commonly, following ingestion a 'raft' of alginic acid is created, floating on the stomach contents by carbon dioxide released by the drug. This forms a mechanical barrier to further reflux. Some preparations also contain antacids to protect the oesophagus.
... 2, the element 2a is zero and it is impossible to divide by it.)
The symbol
<math>\pm \sqrt {b^2-4ac}</math>
in the formula should be understood as ...