Quick Bite. A 2 minute read from Suna's doctors.

Would you drink your own blood for science? The Vampire study

A gastroenterologist on one of the stranger studies in gut medicine, and the quietly moving thing underneath it.

Dr Sam WithingtonGastroenterology Speciality Registrar and Suna's Gut Health Lead

2 min read. Updated .

Researchers in Zurich persuaded sixteen healthy volunteers to swallow their own blood, to settle two questions doctors face constantly: what blood in the gut does to an inflammation test, and how long stools take to return to normal once bleeding has stopped.

It's a tough sell, but scientists in Zurich wanted to understand what blood does to your gut. They managed to convince sixteen healthy people to drink a large glass of their own blood, or have a tube inserted into their stomach via their nose and have the blood pumped in. Having had a friend practice putting a nasogastric tube in on me during medical school, I really can't tell you which option I would go for - ideally, neither. The authors did state that 'All participants tolerated blood ingestion well.' Clearly braver souls than I.

Then they got the volunteers to track any changes in their poo while also testing samples for signs of inflammation in the gut. Aside from being a bit grim I do really like the study, as it addresses two common questions for people in hospital - what is the relationship between bleeding and inflammation and has this person stopped bleeding yet? It's common to have someone come in with say, a bleeding stomach ulcer, put a camera down and treat it, and then get a call two days later that their stool still hasn't gone back to normal.

The study gave useful answers to both problems - the mere presence of blood in the gut caused a modest rise in half of the inflammation tests, and it took about 3-5 days for the volunteers' stools to go back to normal after drinking the blood. This can help save people from having unnecessary repeat tests after bleeding and help gastroenterologists interpret gut inflammation tests better. It also suggests that some medical students will do almost anything for a certificate. So aside from showing the strength of their stomachs, the volunteers did something truly useful for others.

I'm struck by just how much of medical science still relies on human altruism; blood and organ donors, charity fundraisers, study volunteers and those who leave their bodies to science after their passing all play a role in collectively moving us forward. In my first year of medical school we did human dissection. It was definitely profoundly unsettling at the start, but at the end of the year we had a service to thank the people who had volunteered their bodies after death. It was immensely moving, and it was just one of the many ways that we all work together towards better understanding of sickness and health.

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Written by Dr Sam Withington. Last updated 8 October 2026. From Digests.

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