For most people opening their bowels is a regular occurrence that happens either every day or every two or three days. It is a necessary bodily function to help expel any undigested food and other waste products.

Your poo can also tell you a lot about your health, with its colour and consistency revealing more about what’s going on under the surface.

Suffering from constipation or diarrhoea is also often caused by other issues, although this sometimes can be dependent on what you’ve been eating, how much fluid you drink and whether you’ve exercised recently.

One expert warned that runny poo or diarrhoea could be a sign of an overactive thyroid, a condition that can lead to “bulging eyes” among other issues.

Doctor Rhianna McClymont, lead GP at Livi, explained: “Loose poo or diarrhoea may be caused by a gut infection, food intolerances, certain medications, an overactive thyroid, or a disease of the intestine like Crohn’s disease.”

An overactive thyroid is also known as hyperthyroidism.

This occurs when the thyroid gland produces too much of the thyroid hormones.

According to the NHS, the thyroid is a “small butterfly-shaped” gland in the neck, found just in front of the windpipe (trachea).

It produces hormones that affect things such as your heart rate and body temperature.

“Having too much of these hormones can cause unpleasant and potentially serious problems that may need treatment,” the NHS says.

It is possible to have both an overactive (hyperthyroidism) and underactive (hypothyroidism) thyroid.

It is thought around a quarter of patients with hyperthyroidism will experience mild-to-moderate diarrhoea.

However, other symptoms to look for include:

• Nervousness, anxiety and irritability
• Mood swings
• Difficulty sleeping
• Persistent tiredness and weakness
• Sensitivity to heat
• Swelling in your neck from an enlarged thyroid gland (goitre)
• An irregular and/or unusually fast heart rate (palpitations)
• Twitching or trembling
• Weight loss.

But if it’s left untreated it can lead to more serious problems.

This includes issues with the eyes, such as eye irritation, double vision or bulging eyes.

The NHS also lists pregnancy complications, such as pre-eclampsia, premature birth or miscarriage, as a dangerous side effect of hyperthyroidism.

An overactive thyroid can affect anyone, but it’s about 10 times more common in women than men, and typically happens between 20 and 40 years of age.

If you experience symptoms you should speak to your GP.

They can arrange for a blood test to check how well your thyroid is working.

Treatment options include medication, radiotherapy and surgery.