In most major cities around the world, communities of ordinary people – nurses, bar staff, secretaries – are drinking human blood on a regular basis. The question is, why?

In the French quarter of New Orleans, John Edgar Browning is about to take part in a "feeding". It begins as clinically as a medical procedure. His acquaintance first swabs a small patch on Browning’s upper back with alcohol. He then punctures it with a disposable hobby scalpel, and squeezes until the blood starts flowing. Lowering his lips to the wound, Browning's associate now starts lapping up the wine-dark liquid. “He drank it a few times, then cleaned and bandaged me,” Browning says today.

To Browning’s bemusement, he was not quite to his host’s taste. “He said my blood was not as metallic as it should have been – so he was a little disappointed,” he recalls; apparently, diet, hydration and blood group can all make a subtle difference to the flavour. After they had cleaned up, the pair went to a charity dinner in aid of the homeless.

A self-confessed “needle-phobe”, Browning had not been looking forward to the feeding. “I’m actually pretty fearful of anything sharp approaching my skin,” he says. But as a researcher at Louisiana State University, he was willing to go through with it for his latest project: an ethnographic study of the New Orleans “real vampire” community.

There are thousands of people drinking blood in the US alone

Was the blood-feeding a religious ritual, a delusion, or a fetish? Before he had met any vampires, Browning suspected they had just blurred the line between fact and fiction. “I’d assumed that these people were bonkers and had just read too many Anne Rice novels.” 

By the time he had offered himself as a donor, however, his opinions had taken a U-turn. Many real-life vampires have no belief in the paranormal and have little more than a passing knowledge of True Blood or Dracula; nor do they appear to have any psychiatric issues. Instead, they claim to suffer from a strange medical condition – fatigue, headaches, and excruciating stomach pain – which, they believe, can only be treated by feeding on another human’s blood.

“There are thousands of people doing this in just the US alone, and I don’t think it’s a coincidence, and I don’t think it’s a fad,” says Browning.  Their symptoms and behaviour are a genuine mystery.

For many, real-life vampirism is a taboo; over the last few decades, it has come to be associated with gruesome murders such as the notorious case of Rod Ferrell in the US, a deluded killer apparently inspired by a fantasy role-playing game. “When people talk about self-identified vampires, a lot of times these horrible images come to mind,” says DJ Williams, a sociologist at Idaho State University. “So the community has been closed and suspicious of outsiders.” As a result of the stigma, the vampires I've contacted online have asked me to use aliases within this article.

It was not always this way; across history, we can find cases where human blood was considered a bona-fide medical cure. At the end of the 15th Century, for instance, Pope Innocent VIII’s physician allegedly bled three young men to death and fed their blood (still warm) to his dying master, with the hope that it might pass on their youthful vitality.

From what we can tell, most major cities across the world seem to have a vampire community – DJ Williams, sociologist

Later on, it was used to treat epilepsy; the afflicted were encouraged to gather around the gallows and collect the warm blood dripping from recently executed criminals. “Blood was a medium between the physical and spiritual,” explains Richard Sugg at the University of Durham, who recently wrote a book on “corpse medicine” and who is currently writing a volume on vampirism. By drinking the blood of a healthy young man, he says, you were imbibing his spirit and curing whatever afflicted your soul. These treatments only fell out of favour following the Enlightenment, and the onset of a more general sense of prudery that took hold in the 18th and 19th Centuries.

And yet, the practice seems to have lived on among a small group of people. Before the Age of the Internet, they were largely isolated, but through dedicated webpages they have now forged thriving underground networks. “From what we can tell, most major cities across the world seem to have a vampire community,” says Williams.

Thanks to their fear of exposure, these communities have become adept at hiding, a barrier Browning faced when he started his study. “This is not a population who are asking to be found,” he says. He was living in Baton Rouge, Louisiana, at the time, just an hour’s drive from New Orleans, a city famed for its vibrant subcultures. He realised that if he was ever going to get the chance to meet a real vampire, it was now.

Walking the streets at day and night, he began to home in on the places (typically goth clubs) where vampires might hang out. Even at the beginning, he was not too scared about the characters he would meet. “It helps being a guy who is 6ft 4in, and 220lbs,” he says. In fact, his biggest concern was not his own safety, but the vampires. “You could ‘out’ them,” he says – potentially putting their personal and professional lives in jeopardy.

When she smiled, I saw two fangs protruding over her lips. They were atrociously sharp – John Edgar Browning, researcher

Eventually, he found himself talking about his project to the owner of a goth clothes shop, who subtly pointed out a woman standing with her two children in one of the aisles. So Browning sidled up to her, and told her about his study of vampires. “Finally she smiled, and said ‘I think I might know a few’,” he recalls. “And when she smiled, I saw two fangs protruding over her lips.” They were, he says, “atrociously sharp”. Although he subsequently lost contact with “Jennifer”, the encounter encouraged him to proceed, and he eventually formed good relationships with a large group of vampires, whom he interviewed regularly.

In fact, the deeper he delved, the wider and more colourful the spectrum of personalities he uncovered. Although some do wear fangs and sleep in coffins, most take very little interest in the books and films. “This was the late 2000s and they weren’t even watching True Blood!” he says with disbelief. “These people knew about as much as the average person about vampire literature and cinema.”

Vampirism, it seems, comes in many shades. The blood-feeding community held jobs as bar staff, secretaries and nurses; some were church-going Christians, others atheists; often, they were very altruistic. “Vampires aren't always skulking around graveyards, attending goth nightclubs, or feasting at blood orgies,” explains one vampire named “Merticus”.  “There are real vampire organisations who feed the homeless, volunteer in animal rescue groups, and who take up any number of social causes.” 

The identity ‘vampire’ means little to nothing to us. However, when we are blood drinkers, the label is impossible to shake – CJ!, blood-drinker

Importantly, while some vampires are looking for psychic energy that gives them strength, others (known as “med sangs” or medical sanguinarians) believe their need for blood is purely physiological. “The identity ‘vampire’ means little to nothing to us,” says one med sang known as “CJ!” (the exclamation mark is part of her online alias), who I met online. “However, when we are blood drinkers – especially human blood – the label is impossible to shake.”

Renewed vitality

Gently questioning his cohort about the onset of the condition, Browning found the hunger for blood seemed to strike around the onset of puberty. One of the first people Browning interviewed, for instance, had been 13 or 14 years old, when he realised he felt weak all the time, lacking all the energy to run and play sports like his friends. Eventually, while fighting with his cousin, he drew blood, and his mouth brushed against the wound.  “He suddenly felt a lot of vitality,” says Browning. That taste for blood eventually turned into a compulsive hunger.

After consuming seven shot glasses of blood, our digestive system works wonderfully – CJ!

It was a common tale that seemed to resonate with most of the vampires he met. Besides relentless fatigue, other common symptoms appear to include severe headaches and stomach cramps. CJ!, for instance, has been plagued with an irritable bowel, which she says can only be cured after a drink of blood. “After consuming a sizeable quantity (somewhere between seven shot glasses to even a cup), our digestive system works wonderfully.”

CJ!’s friend “Kinesia” paints a similar picture. “I would go more than a week without a bowel movement while ‘hungry’, and feel nausea if I ate anything other than my ‘cure food’,” she says. Describing her apparent relief following a blood meal, she says: “I felt 100% better; my mental faculties were sharpened. I can eat whatever I want, without running to the bathroom, and there is no joint or muscle pain. This tends to last about two weeks, depending on how much is taken and how often it is taken.”

The utmost care is taken of the donor, making sure they are relaxed and willing at all times - Kinesia

Needless to say, donors are hard to come by. How do you possibly ask someone to let you drink their blood? CJ! says donors are often close friends who understand her perceived needs; Kinesia feeds from her own husband every couple of weeks. In other cases, it may involve some kind of payment, says Browning. Whatever the precise nature of the donor-vampire relationship, it’s always consensual. “The utmost care is taken of the donor – making sure they are relaxed and willing at all times,” says Kinesia.

As Browning himself found, the extraction itself is closer to a medical procedure than a passionate ravishing. Typically, both the donor and the vampire are first tested at sexual health clinics (or regular blood donation centres) for transmissible infections. To make the incision, the vampire may use disposable scalpels or syringes, which they open and clean in front of the donor – and they will swab the skin before the first cut. If they are drinking directly from the wound itself, they are also sure to clean their lips, brush their teeth and gargle mouthwash beforehand.

Alternatively, they may have more advanced medical knowledge; CJ!’s paraphernalia includes a tourniquet and intravenous draw. Before taking the blood, she gives the donor a small rubber mouse to squeeze, which makes it easier for her to find the vein. If they have the luxury, the vampires refrigerate an excess, which they mix with an (edible) anticoagulant and store in sealed “vacutainers”. Failing that, Browning says that some vampires will make a concoction with tea and herbs, which apparently also helps preserve the blood for longer.

 “The sang community as a whole is very careful and conscientious about health and safety,” says “Alexia” in the UK, who researched phlebotomy before attempting an intravenous draw. The feeding itself, she says, is “impersonal, much like taking a pill.”

The community as a whole is very careful and conscientious about health and safety – Alexia

Following feeding, the vampires do not seem to suffer any ill side-effects; although ingesting a large volume of iron could be toxic, the amount consumed in a feeding does not seem to constitute a danger. “No vampire I’ve interviewed has complained of any medical complications as a result of consuming blood,” Browning says. Even so, Tomas Ganz at the University of California Los Angeles points out that they cannot completely eliminate the risk of infection. “Testing in sexually transmitted disease clinics does not cover the full spectrum of potentially transmissible diseases, but should cover the more common ones such as HIV or hepatitis B and C,” he says.

The best way to get a real measure of the dangers would be to study official medical records. Unfortunately, most vampires are too afraid of the stigma to tell doctors or social workers of their habit. “We had one person say that if a clinician found out I was a vampire, they’d take my kids away,” says Williams, who has studied the possible effects the stigma may have on the vampires' healthcare.

A few, like CJ!, are becoming more open; she has discussed her blood-feeding with both a gastrointestinal surgeon, and a psychiatrist. “Both have been supportive, although sadly neither had any insight beyond the immediate issue at hand,” she says.

Far from relishing the blood drinking, the vampires I’ve spoken to are desperate to find a more socially-acceptable treatment

Indeed, far from relishing the ritual of blood drinking, most of the vampires I’ve spoken to would happily give it up – but so far, they say doctors have apparently failed to find other ways to relieve their symptoms. “Many of us would rather not go through the cyclic symptoms and just be happy to live life like a normal person,” says Kinesia. Alexia agrees: “If the cause could be identified, I would most certainly take a pharmaceutical pill.” One of their own theories is that they have some problem with their digestive tract, which means they cannot absorb nutrients from usual foods – it is only when they are readily dissolved in blood that their bodies can access them.

The vampires are, however, disarmingly open about the possibility that their experiences may be psychosomatic. “This could very well be in our heads,” admits CJ!. For this reason, some of the vampires have tried to stop feeding on blood, to see if the symptoms would just go away – but so far without success. “For me, one scary moment was when I was admitted to ER for having a low heart rate that would jump up to 160 when I stood up, or walked around, followed by a massive migraine, and often losing consciousness,” says Kinesia. “Basically, my heart was working extra hard to keep everything functioning – a reaction, I believe, to about four months without feeding.”

Doctors are still getting to grips with the way our brain can control our health in a very real, physical way

Ganz suggests that the relief that comes with drinking blood could be largely psychological; doctors are still getting to grips with the way our brain can control our health in a very real, physical way. “There is likely a strong placebo effect, akin to ingesting bitter powders, brightly coloured liquids, or other substances that do not look or taste like conventional foods,” says Ganz. “This effect can be further enhanced if there is a ritual component associated with the ingestion, and if the individual feels a sense of some kind of exclusivity (such as drinking a very expensive and rare wine).” Combined with the fact that blood is highly nutritious, and a natural laxative, he thinks this may be why it offers some temporary relief for both the digestive and mental difficulties.

Some may question whether a thirst for blood is sometimes a sign of deeper underlying mental health issues. But Steven Schlozman, at Harvard University, says that diagnosing these people could be something of a “tightrope”. “I know that if a patient came to me with this issue as a complaint or was worried about the practice, my first response as a psychiatrist would be to assess for psychosis since the practice is so far outside of culturally normally done behavior,” he says. Still, he would keep an open mind, and explore whether they were genuinely benefitting from the practice. Certainly, Browning and Williams both say that through their extensive contact with these people, they saw no evidence of psychiatric difficulties. Joseph Laycock at Texas State University, who has also studied vampire identity, agrees: “They had different premises but they thought about it logically – they proceed logically from the need to drink blood.”

It is an interesting case study of a prolonged and difficult discussion in psychiatry – just how do you avoid medicalising harmless but unusual activities, without accidentally missing people who genuinely need help? “We have a collective tendency to label unconventional behaviours as psychiatric abnormalities,” says Ganz. “But I have no basis for describing it as such if the individual and their donor are comfortable with their unconventional nutrient choice.”

Perhaps now the vampire community is opening to outsiders, scientific enquiry will be able to explore these questions and finally offer some answers. In the meantime, a group of vampires, led by Kinesia, are taking the first steps themselves. Using commercial companies such as 23andme and uBiome, for instance, she is starting to profile the genes and microbiomes of other med sangs. “The point of inquiry is not about validation for our ‘vampirism’. It is to find more socially practical ways to fulfil whichever deficiency or need that we ultimately have, basically we are seeking more treatment options,” says CJ!.

Whatever they find, Browning’s encounters have taught him that we should treat them with the same respect we afford other minority groups. “When I first went into the study, I just assumed I’d meet kooky people, but within a year, I realised that vampires didn’t have the problem. It’s us non-vampires that have had the perceptual problem.”

Just because we don’t yet understand their experiences, doesn’t mean we should scorn them or dismiss them out of hand, he argues. The vampire identity is, after all, a way for some people to cope with mysterious and debilitating feelings. “What’s happening to them is real. We don’t understand what it is, and they don’t understand what it is – but they are doing their best to deal with it.”

David Robson is BBC Future’s feature writer. He is @d_a_robson on twitter.

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