Antacid remedies neutralise stomach acid and are generally considered first-line treatment, after or alongside lifestyle changes. Aluminium and magnesium salts frequently form the base of these products, sometimes in combination so the respective side effects of constipation and diarrhoea cancel each other out. Antacids can react with other medicines, so it is always important to ask customers if they are taking anything else when recommending or selling such products.

Alginates, or rafting agents, form a layer that sits above the stomach contents and stops them leaking into the oesophagus.

Liquids have a quicker effect than tablets, which should always be sucked or chewed rather than swallowed, and all products are best taken about an hour after eating, rather than immediately.

OTC examples include Gaviscon Advance, Bisodol and Rennie. Some products contain both an alginate and an antacid (e.g. Gaviscon Double Action).