Merycism (Rumination Syndrome)

Merycism, also known as rumination syndrome, is a chronic condition where undigested food repeatedly comes back up from the stomach into the mouth shortly after eating, without nausea or pain—an involuntary reflex that can affect anyone from infants to adults.

Table of contents

• What is Merycism?
• Other Names for This Condition
• Signs and Symptoms
• What Causes Merycism?
• Who is Affected?
• How is it Diagnosed?
• Treatment Options
• Possible Complications
• Outlook and Recovery

What is Merycism?

Merycism, more commonly called rumination syndrome, is a chronic motility disorder (a condition affecting how muscles move food through the digestive system) where food repeatedly comes back up from the stomach into the mouth after eating^[1]. This happens because of involuntary contractions of the muscles around the abdomen^[1].

What makes merycism different from typical vomiting is that the food comes back up effortlessly, without the unpleasant symptoms that usually accompany being sick. There is no retching, no nausea, no heartburn, no unpleasant smell, and no abdominal pain^[1]. The regurgitated food is still largely undigested and hasn’t mixed much with stomach acid, so it doesn’t taste sour or bitter like vomit does^[1][6].

Once the food comes back into the mouth, a person may rechew it and swallow it again, or they may spit it out^[1][2]. This pattern typically happens after every meal and is automatic—often the person doesn’t do it on purpose^[6].

Rumination syndrome, Rumination disorder

Other Names for This Condition

Merycism is known by several other names in medical practice. The most common alternative name is rumination syndrome, which comes from the Latin word “ruminor,” meaning “to chew over again”^[9]. Healthcare providers also sometimes call it rumination disorder, particularly when discussing it as an eating disorder^[2][6].

Signs and Symptoms

The hallmark symptom of merycism is the repetitive regurgitation of undigested food after the start of a meal^[1]. While the severity varies from person to person, this regurgitation is always present.

In some people, the regurgitation is small and occurs over a long period following eating. The food can be rechewed and swallowed again. In others, the regurgitation can be more forceful and brief, and must be expelled from the mouth^[1]. Some individuals experience symptoms after only certain meals, but most have episodes following any food or drink intake, from a single bite to a large meal^[1].

Symptoms can begin anywhere from immediately after ingestion to two hours later^[1]. However, the most common timeframe is between thirty seconds and one hour after finishing a meal^[1]. The regurgitation typically occurs within fifteen minutes of eating and can be repeated for up to two hours^[9].

Unlike typical vomiting, the regurgitation is described as effortless and unforced^[1]. There is seldom nausea before the food comes back up, and the undigested food lacks the bitter taste and smell of stomach acid^[1]. Symptoms tend to stop when the ruminated contents become acidic^[1].

Additional symptoms that may occur include:

• Weight loss (unintentional)^[2][5]
• Bad breath (halitosis)^[2][5]
• Tooth decay^[2][5]
• Raw and chapped lips^[2]
• Repeated stomach aches and indigestion^[2]
• A feeling of fullness or bloating^[11]
• Abdominal pain (in some cases)^[5]

In infants and babies, merycism can cause unusual movements. These include straining and arching the back, holding the head back, tightening the abdominal muscles, and making sucking movements with the mouth^[2][6]. These movements may occur as the infant tries to bring the partially digested food back up.

What Causes Merycism?

The exact cause of merycism is not fully understood by doctors and researchers^[2][5][6]. However, several factors appear to contribute to its development.

From a physical standpoint, regurgitation happens because certain muscles relax or contract at the wrong time. The lower esophageal sphincter (the muscular valve between the esophagus and stomach) is supposed to open when you swallow and then close to keep food in the stomach. In merycism, pressure within the belly triggers abdominal muscles to contract, pushing food back up. At the same time, the lower esophageal sphincter relaxes in response to this pressure, like a release valve, allowing food to rise back into the mouth^[12].

Several factors may contribute to triggering or maintaining merycism:

• Physical illness or severe stress may trigger the behavior^[2][5]
• Increased abdominal pressure^[5]
• Chronic constipation^[5]
• A relaxed lower esophageal sphincter^[5]
• Problems with how the digestive system and brain communicate with each other^[6]
• Recent surgery, psychological distress, or concussion^[5]
• An initial illness, such as a virus, that caused vomiting^[6]

Many experts believe merycism is a learned response. When children have a stomach virus or illness that causes vomiting, they often feel uncomfortable. This creates anxiety about throwing up again, which can cause increased stomach sensitivity. The body learns that tightening the belly and bringing food back up provides relief from this discomfort. Once learned, this response can become automatic and continue even after the original illness has resolved^[6][11].

For some individuals, particularly children, the act of rechewing food may become a source of comfort when feeling worried or stressed^[2][6]. Neglect or an abnormal relationship between a child and their mother or primary caregiver may cause the child to rely on self-comfort through this behavior^[2].

Who is Affected?

Merycism can affect people of all ages, from infants to adults. Historically, the condition was documented mainly in infants, young children, and people with cognitive disabilities^[1]. Among institutionalized patients with various mental disabilities, the prevalence can be as high as 10 percent^[1].

However, the condition is increasingly being diagnosed in otherwise healthy adolescents and adults^[1]. Rumination disorder is most common in babies and very young children between 3 and 12 months of age, and in children with cognitive impairments^[2]. It is rare in older children, adolescents, and adults, but does occur^[2].

Research suggests that approximately 1 in 125 people in the general population experience merycism, though the actual number is likely higher because the condition often goes unrecognized^[15]. It occurs more commonly in people who have been diagnosed with certain conditions. About 1 in 10 people with fibromyalgia may experience merycism^[15]. Similarly, between 1 in 10 and 1 in 20 people with eating disorders may also have rumination syndrome^[15].

In children and adolescents without developmental difficulties, merycism is more common in females than males. However, in adults, it occurs equally in both males and females of all ages^[15].

Many people with merycism also have a diagnosis of anxiety and depression. However, it is not known whether mental health problems precede the condition or develop as a result of living with merycism, as the symptoms and delays in diagnosis can negatively affect quality of life^[15].

Most young children with rumination syndrome outgrow it naturally. In children aged 10 and older, though, the condition can last longer and be more difficult to manage^[6].

How is it Diagnosed?

Diagnosing merycism can be challenging because its symptoms resemble those of other digestive disorders. Many people are misdiagnosed or go undiagnosed for extended periods due to the similarity between rumination syndrome and conditions like gastroesophageal reflux disease (GERD, a condition where stomach acid frequently flows back into the esophagus), bulimia nervosa (an eating disorder), and gastroparesis (delayed stomach emptying)^[1][5].

The diagnosis of merycism is primarily based on a detailed medical history and observation of symptoms^[1][6]. Healthcare providers will ask about current symptoms, when they began, and what triggers them. They may inquire about the taste of the regurgitated food—if it doesn’t taste acidic, it means the food wasn’t fully digested, which suggests merycism rather than vomiting^[5].

For a diagnosis to be made, certain criteria must be met. The person must have been able to eat and digest food normally before the problem started, and the issue should not be due to another medical condition^[2]. The regurgitation must have been ongoing for at least one month^[2][4]. The behavior usually happens during eating or right after^[2].

With infants and young children, doctors may need to review eating habits and observe the child during and after feeding to make an accurate diagnosis^[2].

To rule out other possible causes of symptoms, healthcare providers may perform several tests:

• Upper endoscopy: A thin tube with a camera (endoscope) is used to examine the esophagus, stomach, and upper part of the small intestine to look for any blockages or abnormalities^[17]
• Gastric emptying tests: These measure how long it takes for food to move from the stomach to the small intestines^[5]
• X-rays: These help investigate the inside of the esophagus and stomach^[2][5]
• Blood tests: These can check for signs of dehydration and malnutrition and rule out other gastrointestinal conditions^[2]
• High-resolution esophageal manometry and impedance measurement: This specialized testing shows whether there is increased pressure in the abdomen and can confirm the diagnosis by demonstrating irregular function^[17]

It’s important to rule out other medical conditions before confirming a diagnosis of merycism^[15].

Treatment Options

Treatment for merycism focuses primarily on changing behavior patterns, with promising results. Upwards of 85 percent of individuals respond positively to treatment, including infants and people with mental disabilities^[1].

The main treatment approach is behavioral therapy, specifically habit-reversal behavior therapy^[17]. This type of therapy is used for people without developmental disabilities who have rumination syndrome. The treatment involves several steps:

First, individuals learn to recognize when rumination is happening or about to happen. When rumination begins, they use their abdominal muscles to practice a specific breathing technique called diaphragmatic breathing^[17]. The diaphragm is a large, dome-shaped muscle located at the base of the lungs^[5]. This breathing technique prevents abdominal contractions and stops regurgitation from occurring^[17].

Biofeedback (a technique that teaches people to control bodily processes) is often part of behavioral therapy and helps individuals learn to control the breathing technique^[17].

Several behavioral approaches may be used in treatment, including:

• Breathing exercises performed after eating^[2]
• Changing posture during and right after eating^[2]
• Encouraging more interaction between mother and child during feeding (for infants and young children)^[2]
• Removing distractions during feeding^[2]
• Making feeding a more relaxing and enjoyable experience^[2]
• Finding ways to distract when the rumination behavior begins^[2]

For some people, finding activities they enjoy can help manage the condition. Engaging in creative activities like art, dance, or hobbies can serve as healthy coping mechanisms and distractions^[21].

Possible Complications

If left untreated, merycism can lead to several health complications. The repeated bringing up of food can cause nutritional problems. People may not get enough vitamins, minerals, and protein, which are essential for good health^[6]. Children may not grow properly, and anyone with the condition could become dehydrated (having too little water in the body)^[6].

The continuous presence of regurgitated food in the mouth can lead to dental problems. Tooth decay and erosion of tooth enamel are common complications^[1][5]. People may also experience bad breath and chapped lips^[1].

When food comes back up, there is a risk that it could be accidentally inhaled into the lungs. This can cause choking or breathing problems. In severe cases, it can lead to pneumonia if food particles enter the lungs^[6].

Beyond physical health, merycism can significantly impact mental and emotional wellbeing. The condition can adversely affect normal functioning and social lives^[1]. Children and adults with rumination disorder may feel stressed and embarrassed by their symptoms^[6]. They may have trouble participating in normal routines and activities, such as attending school, work, or sports^[6]. The condition has been linked with depression^[1].

Additional potential complications include:

• Acid regurgitation and damage to the esophagus^[12]
• Electrolyte imbalances^[12]
• Severe weight loss and malnutrition^[1]

Outlook and Recovery

The outlook for people with merycism is generally positive, especially with proper treatment. Treatment is promising, with more than 85 percent of individuals responding well to behavioral therapy^[1]. This includes infants, children, and adults, as well as people with developmental disabilities.

Most young children with rumination syndrome naturally outgrow the condition over time^[2][6]. For children aged 10 and older, and for adults, the condition may last longer and require more intensive management through behavioral therapy^[6].

Success in managing merycism often depends on early recognition and appropriate treatment. Because the condition can be mistaken for other digestive disorders, delays in diagnosis can lead to prolonged symptoms and reduced quality of life. However, once correctly diagnosed and treated with behavioral approaches like diaphragmatic breathing, most individuals can learn to control the regurgitation and return to normal eating patterns.

The key to long-term success is consistent practice of the behavioral techniques learned during treatment. With proper management, people with merycism can avoid complications, maintain good nutrition, and participate fully in daily activities without the disruption caused by frequent regurgitation.