Asked by: Nicola Bain, Glasgow
Vomiting is a deliberate response by the body that evolved as a purging mechanism to remove toxins or foreign bodies from the stomach and oesophagus. Since stomach contents are highly acidic, vomiting can be quite harmful for the throat, mouth and teeth and salivating helps to reduce this by diluting and rinsing.
Saliva is also weakly alkaline, which helps to neutralise acid.
Luis trained as a zoologist, but now works as a science and technology educator. In his spare time he builds 3D-printed robots, in the hope that he will be spared when the revolution inevitably comes.