How Do Drugs Affect the Digestive System?

The gastrointestinal system is made up of the mouth, throat, esophagus, stomach, pancreas, small intestine, large intestine, rectum, and anus.¹ It also includes the liver, salivary glands, gallbladder, and pancreas. Chronic substance use can damage these organs and potentially cause cancer in all parts of the digestive system.²

This article will examine the many ways in which alcohol and commonly misused drugs can harm the gastrointestinal system.

How the Body Processes Abused Substances

The specific substance of abuse and route of administration can determine the type and extent of damage to the gastrointestinal system; however, the consequences to the digestive system can reach far beyond the initial obvious signs and symptoms.

Substances taken via the mouth travel through the entire digestive system and may damage each organ along the way. For example, chronic use of alcohol—typically ingested orally—is associated with an increased risk of several types of cancer, including esophageal cancer and cancers of the throat, larynx, liver, colon, and rectum.³

The liver and kidneys—organs vital to the digestive system—are damaged by the chronic substance use of any kind, even when drugs bypass other parts of the gastrointestinal system. For example, injecting heroin directly into a vein still damages the liver and the kidneys, since blood passes through these organs for filtration and metabolization.⁶

What Causes Stomach Pain After Drug Use?

Drug or alcohol-induced stomach pain can range from mild to severe and may indicate everything from irritation to a potentially life-threatening health problem such as an ulcer or internal bleeding. .⁷

Abdominal pain and nausea are common side effects of drugs like:⁶

• Cocaine.
• Heroin. 
• Prescription opioids.
• MDMA.
• Ayahuasca.

Drug-induced stomach pain can indicate gastritis, an inflammation of the stomach lining⁾ that can lead to ulcers or cause bleeding in the lining of the stomach.^8,9

Stomach pain or discomfort can also be a symptom of withdrawal. For example, common opioid withdrawal symptoms include vomiting and diarrhea.⁶ At first glance, vomiting and diarrhea during detox may appear to be merely uncomfortable withdrawal symptoms; however, persistent vomiting and diarrhea can cause dehydration which can result in electrolyte imbalances requiring acute medical attention. ¹⁰

Medically managed detox can drastically reduce the risk of serious withdrawal complications and ease discomfort.¹¹

Chronic Substance Use and Malnourishment

Nutrient deficiencies due to chronic alcohol and drug use need to be addressed in treatment as well.¹⁰ Malnourishment among people struggling with addiction may be caused by several factors:¹²

• People with substance use disorders often have chaotic lifestyles and disordered eating habits; for instance, money may be spent on drugs or alcohol instead of food.
• Drugs and alcohol affect people’s appetites as well; alcohol can be filling and a replacement for food, while certain drugs, like many stimulants, actually decrease a person’s appetite.
• Substances can also affect the kinds of food people choose to eat. For example, people that chronically use cocaine often prefer foods high in refined carbohydrates and fat, and their diets often lack fresh fruits and vegetables. People addicted to opioids often eat sugar and alcohol-rich foods instead of protein and fats, possibly leading to a nutrient deficiency.

Alcohol Use and the Gastrointestinal System

As mentioned previously, heavy, chronic alcohol use can cause several different types of cancer, including many cancers related to the gastrointestinal system.¹³

There are multiple ways alcohol increases a person’s risk of certain cancers:¹³

• In order for the body to metabolize the ethanol in alcoholic beverages, it must turn it into acetaldehyde, which is a likely human carcinogen that can damage DNA.
• Alcohol impairs the body’s ability to metabolize various nutrients that are vital to our health, such as vitamins A, C, D, and E, folate, and carotenoids.
• Alcohol consumption can cause hormonal imbalances, especially in relation to estrogen, causing an increased risk of breast cancer.
• There are often carcinogens that are contaminants of the alcohol itself, including asbestos fibers, hydrocarbon, and nitrosamines.

Giving up alcohol is an essential step in beginning to heal the damage caused by drinking, a decision that may require professional help for alcohol addiction.¹¹

How Stimulants Damage the Digestive System

Cocaine, methamphetamines, and prescription stimulants are typically either taken orally, in a pill form or rubbed into the gums, or they may be snorted or smoked.^14,15 The damage caused to the digestive system by these stimulants can be significant.

Addiction to stimulants can damage the gastrointestinal system in a variety of ways:

• Chronic use of cocaine can cause a lack of blood flow to the stomach and intestines, causing dead (ischemic)bowel tissue.⁶
• Chronic use of methamphetamines can cause severe dental problems, diarrhea, constipation and stomach cramping.^16,17
• Stimulant drug use can cause a significant decrease in appetite, leading to nutritional deficiencies and weight loss.⁶

Opioid Use and the Digestive System

Opioid drugs include several prescription painkillers, as well as illicit drugs like heroin. Opioids can be ingested orally in the form of a pill, or they can be smoked, snorted, or injected directly into a vein.⁶

Opioids cause so many gastrointestinal issues that a condition called opioid-induced bowel dysfunction (OIBD) had been identified to explain the potentially-debilitating effects of chronic opioid use on the digestive system.¹⁸ Common complaints of OIBD include:¹⁸

• Nausea.
• Vomiting.
• Diarrhea. 
• Decreased gastric emptying, which can lead to reflux, stomach cramping, and bloating.

Help for Drug or Alcohol Addiction

Sunrise House Treatment Center, in Lafayette, New Jersey, has been providing rehab services for over 40 years and is close to the New York City metro area. The first step is the start the admissions process.

Compassionate admissions navigators are available at to answer questions and guide you through the necessary steps.  If you are unsure how to pay for treatment, they can help you understand the options available, including using insurance to pay for rehab and payment plans.

Sunrise House Treatment Center offers various levels of care that include medical detox, residential treatment, and aftercare planning. Whatever your individual needs may be, they can help. Call to learn more. Why wait another day?