Bulimia nervosa affects nearly every system in the body, from the heart and kidneys to the teeth and reproductive organs. Some of these consequences develop within weeks of regular purging, while others build silently over years. People with bulimia have roughly twice the mortality risk of the general population, with a standardized mortality ratio of 2.20 compared to those without the disorder. Understanding what bulimia does to the body can clarify why early intervention matters and which effects can still be reversed.
Heart Rhythm and Electrolyte Disruption
The most immediately dangerous consequence of bulimia is the loss of electrolytes, especially potassium. Vomiting, laxative abuse, and diuretic misuse all drain the body of potassium, sodium, and chloride in different combinations. When potassium drops low enough, the electrical signals that keep the heart beating in rhythm start to malfunction. This shows up as a prolonged QT interval on a heart monitor, which is a recognized risk factor for sudden cardiac death.
A prolonged QT interval means the heart muscle takes too long to recharge between beats, creating conditions for dangerous rhythm disturbances. When potassium falls below about 2.3 milliequivalents per liter (normal is 3.5 to 5.0), the risk of a type of erratic heartbeat called ventricular fibrillation rises sharply. This can be fatal. The good news is that mild electrolyte imbalances typically correct themselves once purging stops and the person rehydrates, but severe or repeated episodes cause cumulative stress on the heart.
People who use ipecac syrup to induce vomiting face an additional threat. Ipecac contains a compound that is directly toxic to heart muscle and can cause potentially irreversible damage to the heart’s ability to pump effectively.
Kidney Damage From Chronic Purging
Persistently low potassium doesn’t just affect the heart. Over time, it damages the tiny tubes inside the kidneys that filter waste from the blood. This condition, called hypokalemic nephropathy, starts with subtle changes to kidney cells (vacuolization and swelling) and can progress to extensive tissue death within those tubes. The combined effects of dehydration and low potassium cause reduced blood flow to the kidneys, trigger inflammation, and promote scarring.
Chronic kidney disease from prolonged purging can progress to the point of requiring dialysis, even in young patients. People who use multiple purging methods (vomiting plus laxatives, for example) face compounded risk. Unlike electrolyte levels, which bounce back relatively quickly, structural kidney damage may be permanent.
Damage to the Esophagus and Stomach
Repeated vomiting puts intense physical pressure on the junction where the esophagus meets the stomach. This pressure can tear the lining, producing what’s known as a Mallory-Weiss tear: a longitudinal rip in the inner lining that can bleed into the digestive tract. Most of these tears stay in the surface layer and heal on their own, but some extend deeper into blood vessels and cause significant bleeding.
In rare cases, the tear goes all the way through the esophageal wall. This full-thickness rupture (Boerhaave syndrome) is a surgical emergency because stomach contents leak into the chest cavity and can cause a life-threatening infection. Beyond acute tears, chronic vomiting also irritates the throat and voice box. These symptoms generally improve once vomiting stops, especially with medications that reduce stomach acid production.
Tooth Erosion and Oral Health
Stomach acid is highly corrosive to tooth enamel, and people who vomit regularly develop a distinctive pattern of erosion. The damage concentrates on the inner (tongue-side) surfaces of the upper front teeth, since those surfaces face the stream of acid during vomiting. In one clinical study, about 42% of erosive lesions appeared on these inner surfaces, with another 37% on the chewing surfaces of molars. The most severe damage, where the protective enamel is completely gone and the softer layer underneath is exposed, tends to appear on the chewing surfaces of lower molars and the inner surfaces of upper front teeth.
This erosion pattern is distinctive enough that dentists sometimes recognize it before a patient has disclosed their condition. Importantly, dental erosion is irreversible once it occurs. Enamel does not regenerate. Restorative dental work can repair the appearance and function of damaged teeth, but the original tooth structure is permanently lost.
The salivary glands, particularly the parotid glands near the jaw, often swell in response to repeated vomiting, giving the face a rounded or puffy appearance. This swelling typically resolves once purging stops. If it doesn’t subside, that’s a strong indicator that purging is continuing.
Visible Signs on the Hands
People who use their fingers to trigger vomiting often develop calluses, abrasions, or small scars on the back of the hand over the knuckles. These marks, called Russell’s sign, form from repeated contact between the upper teeth and the skin during the act of self-induced vomiting. The lesions appear on the skin overlying the knuckle joints and finger joints and can range from subtle redness to thickened, hardened calluses.
Mental Health and Co-occurring Disorders
Bulimia rarely exists in isolation. The lifetime rate of major depression among people with bulimia is estimated at 79%, compared to about 23% in the general population. Depression typically develops after bulimia has already taken hold, suggesting the eating disorder itself contributes to mood disturbance rather than simply co-existing with it.
Anxiety disorders affect roughly 60% of people with bulimia, spanning generalized anxiety, panic disorder, social anxiety, and obsessive-compulsive patterns. Post-traumatic stress disorder occurs in about 45% of people with the condition, and ADHD in about 35%. Substance use is also common: the lifetime prevalence of an alcohol use disorder in people with bulimia is estimated at 46%, and about 26% report illicit drug use. These overlapping conditions complicate treatment, since addressing the eating disorder alone without treating depression or substance use tends to produce poorer outcomes.
Reproductive and Pregnancy Risks
Most women with bulimia experience menstrual irregularities even when their body weight is in the normal range, and about 5% develop secondary amenorrhea (loss of periods after previously having them). These disruptions can lead to difficulty conceiving, which is sometimes the reason a person first seeks medical attention.
For those who do become pregnant, bulimia increases the risk of miscarriage significantly compared to the general population. A large cohort study found that women with bulimia were more likely to miscarry, while those with any eating disorder history had higher rates of premature labor, low birth weight babies, and restricted fetal growth, particularly if the mother’s BMI was below 20. Maternal complications include a higher rate of severe nausea during pregnancy, postnatal depression, and anemia.
Bone Density: Lower Risk Than Expected
Unlike anorexia nervosa, which causes significant bone loss, bulimia at a normal body weight does not appear to carry a major risk for osteoporosis. In a follow-up study comparing bone density in people with anorexia versus bulimia, over half of the anorexia group had osteoporosis at the spine, while only one person with bulimia (about 8% of the group) showed even mild bone thinning. Both recovered and non-recovered bulimic patients maintained bone density within the normal range. This distinction matters because it’s one area where the consequences of bulimia are notably less severe than those of anorexia, provided the person has not had a previous history of anorexia with significant weight loss.
What Can and Can’t Be Reversed
Some consequences of bulimia resolve once purging stops, and some don’t. Knowing the difference helps clarify what recovery can realistically achieve.
Electrolyte imbalances, including low potassium and low sodium, generally correct within days to weeks of stopping purging behaviors and rehydrating. Throat and voice box irritation improves with cessation of vomiting, and acid-suppressing medication can speed this along. Parotid gland swelling typically goes down on its own. Metabolic alkalosis, an acid-base imbalance common in people who purge frequently, is usually correctable with fluid replacement.
Dental erosion, on the other hand, is permanent. So is kidney damage that has progressed to chronic kidney disease. Heart muscle damage from ipecac use may also be irreversible. The psychological consequences, while treatable, often require sustained therapy and sometimes medication, especially when depression or substance use disorders are deeply entrenched.
The pattern is clear: the sooner purging stops, the more the body can recover. Electrolytes and soft tissue heal well. Enamel, kidney structure, and heart muscle do not.