Have you ever looked at a bar of soap and wanted to take a bite? It’s not as uncommon as you might think.

Pica is a mental health disorder that causes a desire or compulsion to eat items with no nutritional value. People with pica might want to eat sand, clay, ice, or even flakes of paint.

One of the more common items that people with pica sometimes want to eat is bar soap. The desire to eat soap even has its own classification, called sapophagia.

Most types of body soap, shampoo, and conditioner are nontoxic (even if they aren’t intended to be edible). Yet eating a bite or two of soap may cause some indigestion or vomiting, in addition to other symptoms.

Over time, repeatedly eating soap can lead to health complications.

Eating soap can have some harmful side effects. Eating a small amount of soap might not do permanent damage to your body, but it really depends on what type of soap you ingest and how much.

Eating soap can cause nausea, vomiting, and diarrhea

Almost all soaps have a highly alkaline pH, according to a 2019 study. This means that eating it can upset your digestion and irritate the lining of your digestive tract.

What’s more, commercially available soaps typically contain acids (like lauric acid or stearic acid) as well as ingredients that come from plants (like essential oils and fragrances). Even if these ingredients are “all natural,” they are not food-grade.

That means eating soap can lead to more than a little discomfort, as well as vomiting. Your body may have difficulty digesting the soap, which can cause diarrhea or even blood in your stool.

Eating soap can cause inflammation in other parts of your body

Eating soap can cause your tongue, throat, and other parts of your body to swell. This can be a temporary reaction to harsh ingredients in the soap or a symptom of an allergy.

Either way, it can be uncomfortable and, in some cases, make it difficult to breathe or swallow.

Eating soap can damage your liver

Part of your liver’s job is to filter toxins out of your bloodstream so that those toxins don’t harm your organs. Eating a large amount of soap puts stress on your liver as it works to get nonedible ingredients out of your body.

Eating soap can increase your risk of cancer

Some ingredients of soap are fine when applied topically but are known to act as carcinogens when they are ingested on a regular basis.

Cocamide DEA, for example, is a chemically modified form of coconut oil that was found in at least 98 shampoo and soap products as recently as 2013.

The causes of sapophagia can vary.

Pica can be caused by nutritional deficiencies, such as a lack of iron or zinc in your diet.

It’s also more common during pregnancy, perhaps because of the rapidly shifting nutritional needs of your body if you’re pregnant.

In older adults, conditions like Alzheimer’s and dementia can lead to the desire to eat soap. A 2019 case study showed that a high percentage of older adults who eat soap may do so as a symptom of dementia.

Some people want to eat soap because it’s a learned behavior that was demonstrated in their family or cultural setting.

Children may eat soap out of a desire for mischief or pure curiosity. They may eat soap because they don’t know any better and they want to know what it tastes like.

Children may also develop the condition pica, causing them to want to eat soap. One German study from 2018 found that 12 percent of children participating in the study experienced pica, suggesting it may be relatively common among that age group.

Nutritional deficiencies can play a role in the compulsion of children to eat soap.

Mental health conditions and autism may make a child more likely to develop pica. In most cases, pica in children will subside as the child grows older.

Anecdotally, people with pica say that they really enjoy eating soap and have a hard time giving up the habit. However, eating soap can cause damage to your internal organs over the long term, so it’s important to get treatment.

Prevention strategies

One of the first recommended strategies may be to limit your exposure to the kind of soap that you (or your child) feel compelled to eat, according to 2021 research.

For example, you can try taking all the bar soap out of your house and replacing it with shower gel.

Cognitive behavioral therapy (CBT)

A healthcare professional may recommend CBT if limiting your exposure to soap isn’t enough to treat sapophagia.

This method of therapy uses actionable goals as well as mindfulness strategies to help you change unwanted habits and compulsions.

Nutritional supplements

A doctor may do a blood test to determine if a nutritional deficiency is causing your pica. If you are lacking in a mineral such as zinc or iron, a nutritional supplement may take away your desire to eat soap.

It’s true that some soaps claim to be made of food-grade nontoxic ingredients. Sometimes soap is made this way to protect curious young children who like to put soap — and everything else they come across — into their mouth.

Just because soap is made to be nontoxic or “food-grade” doesn’t mean that it is food. You should not consume any type of soap in large quantities, no matter what it’s made of.

If you take a nibble of soap because you’re curious or have tried tasting it once, it’s unlikely you will see side effects besides an upset stomach or a sore throat.

However, if you (or your child) are regularly eating soap or wanting to eat soap, you may want to speak with a doctor about this habit.

Most children and pregnant people naturally stop feeling pica compulsions, but that doesn’t mean you shouldn’t tell your doctor what you’re experiencing.

Some people with long-term pica experience bowel obstructions that may make it difficult to use the bathroom.

This can happen with sapophagia. If you’re experiencing constipation and have been eating soap, you should let a doctor know.

Medical emergency

Call 911 or the Poison Control Hotline at 800-222-1222 immediately if you notice any of the following symptoms after eating soap:

  • burning sensation in your throat or esophagus
  • seizures
  • dizziness or loss of consciousness
  • difficulty breathing
  • vomiting blood
  • irregular heart rate

The desire to eat soap isn’t as uncommon as you might think.

Ingesting a small amount of soap is usually not toxic in the short term, but habitually eating soap can cause complications later on. Eating soap can be an indicator of a nutritional deficiency or mental health condition.

Speak with your doctor if you regularly feel compelled to eat soap. They can recommend the best treatment for you.