Hiccups occur when your diaphragm (the thin layer of muscle that separates your chest cavity from your abdomen) suddenly and involuntarily contracts (tightens).
As your diaphragm contracts, it causes you to breathe in air very quickly. The incoming air is stopped when your glottis (the opening between your vocal cords) closes suddenly, producing the characteristic sound of a hiccup.
Short-term hiccups
Most cases of hiccups occur for no apparent reason. Everyone experiences a short bout of hiccups from time to time. This is perfectly normal and nothing to be concerned about.
The most common causes of short-term hiccups are:
- consuming large amounts of alcohol
- excessive smoking
- a bloated stomach – usually as a result of eating or drinking too quickly
- a sudden change in room temperature
- a sudden change in the temperature inside your stomach
Sometimes, short-term hiccups may also occur as a result of:
- shock
- stress – the feeling of being under pressure
- excitement
See below for more information about psychological factors that can cause hiccups.
People experiencing short-term hiccups usually get better without the need for treatment.
Persistent and intractable hiccups
In rare cases, persistent and intractable hiccups can be caused by a more serious underlying condition, such as gastro-oesophageal reflux disease (GORD) (see below). However, in other cases the cause of hiccups remains unknown (idiopathic).
Several conditions can cause hiccups. However, even with testing and investigation an underlying cause can sometimes not be identified.
Possible underlying conditions
Some of the conditions that can potentially cause long-term hiccups include:
- gastro-oesophageal reflux disease (GORD) – a condition where stomach acid flows back into the oesophagus (gullet)
- gastroenteritis – a stomach and bowel infection that causes repeated diarrhoea (loose, watery stools)
- small bowel obstruction
- gastritis – inflammation of the stomach
- pharyngitis – a sore throat that is usually caused by a viral or bacterial infection
- laryngitis – inflammation of the voice box (larynx)
- goitre – swelling of the thyroid gland
- hypoglycaemia – low levels of sugar (glucose) in the blood
- diabetes – a long-term condition caused by too much sugar (glucose) in the blood
Medication
Persistent hiccups can sometimes be caused by a reaction to certain types of medication. For example:
- anaesthesia – medication that is given before a surgical operation or procedure that causes a loss of sensation
- corticosteroids – medication that reduces inflammation (swelling)
- benzodiazepines – a type of sedative that helps to reduce anxiety
- barbiturates – a type of sedative that are sometimes used to prevent seizures (fits)
- opioids – medication that is used to treat pain; morphine and methadone are both strong opioids
- methyldopa – medication that is used to treat high blood pressure (hypertension)
Psychological factors
Persistent hiccups are sometimes associated with psychological factors. For example, they may occur as a reaction to a strong feeling or emotion such as:
Possible complications
Prolonged hiccups can sometimes cause a number of complications. For example, in some cases it can lead to:
Visit your GP or another healthcare professional if you have hiccups that have lasted longer than 48 hours and you are unsure about what is causing them.
See Hiccups – Diagnosis for more information.
