Pica: The Eating Disorder That Makes You Eat Dirt And Paint

Ever looked at a pile of bricks and thought, "that looks yummy, actually"?


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer

A plate with stones on it and a glass with glass in it
Babe you ok? You've barely touched your rocks and glass. Image credit: Karel Evenhuis/Shutterstock

Pica – that’s “pi-ca” as in pie, rather than “pica” as in Pikachu – is technically classified as an eating disorder. However, superficially at least, it is rather different from its more famous brethren like anorexia or bulimia. It’s not characterized by refusing to eat or rejecting nutrition, but by enthusiastically ingesting things that aren’t food at all.

“Pica is the Latin name for ‘magpie’, a well-known bird that reputedly collects and eats almost anything,” explained Liz Shea, a Clinical Psychologist at the Birmingham Food Refusal Clinic, in a 2019 article for the UK’s National Autistic Society. 


“Pica as a medical term refers to the persistent eating of non-nutritive, or non-food, items,” she wrote. “Pica can be compulsive, very dangerous and preventing it can also be very difficult.”

The things that those with pica find themselves chowing down on range from the seemingly non-problematic – ice, for example, is a common craving, particularly among pregnant people – to the seriously worrying. People with the condition can have very specific preferences, eating things like cloth, paper, chalk and paint, plants and plant material like pinecones, coins, soap, burned matches, dirt, and even poop.

The problem is, we don’t really know all that much more than that about the condition. What exactly causes it, and whether there’s one specific best way to treat it, we simply don’t have enough information to answer. 

“We do not, as yet, know why people engage in pica,” Shea noted. “There are currently no evidence-based treatments for pica and research into this area, particularly with autistic people, is limited and inconclusive.”


So, what, if anything, can we say about this compulsion? How dangerous is it, really? And what can we do about it if we find ourselves driven to scarf down a plateful of loose change?

Who gets pica?

Like almost every condition out there, pica can affect just about anybody. Pica is "reported across the world, and throughout history,” explained Shea, noting that there are "stories of people eating coal and earth documented as far back as Roman times.”

That said, there are some groups who seem to be more likely to be affected – it’s particularly common in pregnancy, for example. One 2020 study in Ghana found that nearly half of the pregnant women studied experienced some form of pica at some point. It crops up on the other side of childbirth, too, with up to one in three children below six showing signs of pica at some point.

The other main group of people who most commonly experience pica are those with intellectual or neurological conditions – including people with autism, learning disabilities, or schizophrenia, among others. “In this latter group pica is reported to be often more severe,” noted Shea. “People engaging in pica often have highly specific preferences […] they are often very motivated in their attempts to obtain their chosen material.”


It's important to be clear about who doesn’t have pica. It’s common in childhood, for example – but as anyone who’s spent time around little kids can tell you, sticking things in their mouths is pretty much par for the course in toddlerdom. That’s why you shouldn’t freak out too much if little Johnny is chewing on a toy puppet right now: pica can’t be diagnosed in children under age two, and diagnosis specifically includes eating nonfood items rather than just exploring them with their mouth.

Eating non-nutritive things for cultural or social reasons doesn’t count, either. It isn’t pica when you pop an antacid, despite it being chemically the same thing as chalk, and it isn’t pica when women in some rural communities in Nigeria eat clay, because both of these seemingly non-nutritive items are seen as normal and potentially beneficial things to eat in their respective societies.

What causes pica?

Pica is a fairly common experience – which means you’d think we’d know something about how and why it occurs, right? 

“We don’t know for certain what causes pica,” said Karen Fleming, a physician in family medicine obstetrics at Sunnybrook Health Sciences Centre in Toronto, in a 2019 Today’s Parent article. “It’s believed to be [due to] an underlying nutritional deficiency, such as iron, or other physical or psychological concerns.”


The idea of pica as a way for the body to try to access vital missing nutrients has a few pieces of evidence behind it. Some studies have shown pica incidence to be associated with iron-deficient anemia, and many others have found that dietary changes to correct such deficiencies can often help stop pica. 

It’s a particularly convincing explanation during pregnancy, too: “Iron deficiency and other deficiencies [such as zinc and iodine] are very common in pregnancy,” Fleming explained, “especially if there is a pre-existing condition or significant morning sickness.”

However, there are definitely cases where nutritional problems aren’t enough to explain why you can’t stop eating bits of brick lately. Some factors like stress, child neglect or abuse, or diagnosed conditions such as schizophrenia or autism spectrum disorders, point to a more psychological explanation for the phenomenon.

“Sometimes, a mother isn’t able to adequately nourish herself due to socio-economic factors or could be suffering from a mental illness and coping with unwanted feelings,” Ottawa dietitian Shawna Melbourn told Today’s Parent. “But, regardless of the reason, it’s not a choice that the mother makes.”

How dangerous is pica?

As you might suspect from a condition defined by compulsively eating inedible things with no nutritional value, pica can have some pretty problematic results. There’s a reason humans, unlike dogs, tend not to eat poop. For example, there are some gnarly infection-causing parasites and bacteria that live in feces, including big hitters like E. coli, salmonella, and the potentially fatal hepatitis A. Similar nasty things can live in the dirt, causing issues for anybody driven to eat soil or clay – two of the most common cravings among pregnant people with pica.

Even things that aren’t actively toxic can be a problem. Have you ever wondered why cats occasionally throw up the odd furball? It’s not complicated: hair just isn’t very helpful inside of our guts. In fact, it can (and does) kill people who eat too much of it. 

Any indigestible items can build up in the gut to form a bezoar – a mass that gets stuck in your body, irritating your insides and causing things like gastric ulcers, internal bleeding, vomiting, fever, weight loss, and more. 

Remember that pica is particularly common during pregnancy: “If women eat non-food items, there is the potential for toxicity and complications for mom and baby,” Fleming pointed out. Even if it’s just ice – another common pica craving during pregnancy – overconsumption can lead to imbalances in electrolytes, leading to metabolic disorders and seizures


In short, Shea said, we should "never in any circumstances assume that pica is a ‘safe’ behavior.”

“Rather, it must always be considered a potentially life-threatening condition,” she warned.

How is pica treated?

As we’ve seen, pica is a poorly understood condition, likely caused by a wide range of interacting factors. It makes sense, then – even if it’s not exactly welcome news to read – that we don’t really have many treatments for the phenomenon.

“Historically, interventions have focused on a variety of methods to reduce or eliminate pica,” Shea explained. “It remains unclear which of these might be the most effective, although behavioral based interventions have been given the most attention in the literature.” 


“Given that pica is likely to involve a number of factors, a combination of approaches is most likely needed,” she added.

Those who suspect a case of pica may stem from nutritional deficiencies, then, might suggest dietary supplementation to treat the condition – and there’s plenty of evidence showing that to be a good idea. But if the condition is being driven by a psychological issue, it may not help at all: in that case, perhaps something like cognitive behavioral therapy would be a better course of treatment. 

Even more complicated are the cases of pica which result from neurological issues. In this case, carers or medical professionals might need to get inventive with their tactics. The parents of James Frankish, a young autistic man who died in 2016 partly due to complications from his pica, would redirect their son’s behaviors using “twiddlers,” or offering edible replacements for inedible cravings.

“Clinical or practice-based interventions that appear to reduce pica […] need to be tailored to each person and come from a thorough understanding of the behavior,” explained Shea. “In general, a multi-disciplinary approach, in other words one that includes the input of a variety of different health professionals working together, is likely to be the most beneficial.”


In all cases, though, there’s one thing that’s probably more important than any other: simply being aware of the condition. Pica can be a source of shame to those who experience it, driving them to keep the behavior secret from support networks who might be able to help. In some cases – such as that of Frankish – the person experiencing pica may even be unable to communicate to caregivers that they are eating non-food items, or are in physical distress from the habit.

In other words: prevention is better than cure. Particularly if you fall into one of the groups at a higher risk for developing pica – and even if you don’t – keep an eye on what your or your loved one’s body says it wants or needs. If it’s telling you something bizarre, especially to the extent that you’re having a hard time ignoring it, then it might be worth talking to someone who can help figure out what’s going on.

“A red flag could be the overwhelming urge to start consuming non-food items,” Melbourn told Today’s Parent. “If this leads to acting on that impulse by ingesting non-nutrition items, that’s a clear indication and you should seek professional help.” 

The content of this article is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of qualified health providers with questions you may have regarding medical conditions. 


If you or someone you know might have an eating disorder, help and support are available in the US at In the UK, help and support are available at International helplines can be found at  


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