The pill is expected to be ready for clinical use by the end of this year, the Volkskrant reported on Friday. The capsule offers an alternative to faecal transplants currently delivered via a nasal tube.

The capsules have been extensively tested in the lab and are designed to withstand stomach acid, releasing their contents only once they reach the intestines, Liz Terveer, medical microbiologist and head of the Dutch national faeces bank at LUMC, told the paper.

Although faecal capsules are already used abroad – such as in the US, where the FDA approved a pill for severe diarrhoea two years ago – they cannot be imported freely due to strict Dutch safety regulations and differences in diet.

This is one reason why the Leiden team is developing a Dutch-made version using faeces from 10 regular donors, the paper said.

Faecal transplants are mainly used to treat patients with antibiotic-resistant diarrhoea, but Dutch studies have shown they can also help leukaemia patients undergoing stem cell transplants. LUMC currently supplies donor material to 66 hospitals across the country.

The capsules are not expected to be quite as effective as frozen donor faeces, because some beneficial bacteria do not survive the production process.

As a result, the pill may not be suitable for all patients, Terveer said. To match the effects of a single transplant, patients may need to swallow around 30 capsules.

Each batch of donated faeces undergoes double screening to prevent contamination, the paper said.