November 14, 2026, 7:39 am | Read time: 8 minutes
Cocaine is available from dealers, alcohol at the supermarket. But does legality really indicate which drug is more dangerous? FITBOOK spoke with a physician who knows the effects of both substances from his clinical experience.
Dr. Johannes Klaus is an addiction specialist at the University Hospital Tübingen, where he treats people with alcohol and drug dependencies. In the FITBOOK interview, he explains the specific risks of alcohol and cocaine and why the question of which drug is more dangerous is not easily answered. In Germany, alcohol is associated with an estimated 47,500 deaths per year.1 In 2025, a total of 2,150 deaths were recorded from illegal drugs.2 In 58 cases, cocaine or crack poisoning alone was recorded; cocaine was more often part of a dangerous mix of substances.
“You can’t rank which is more dangerous”
FITBOOK: Dr. Klaus, when comparing alcohol and cocaine directly, can you say which of the two substances is more dangerous?
Dr. Johannes Klaus: “That can’t be answered in general terms. However, when you drink beer, you usually know what’s in it. That’s not the case with cocaine. Therefore, cocaine is harder to control. But it’s difficult to establish a general ranking of which is more dangerous.”
What exactly happens in the body when you drink alcohol or take cocaine?
“With alcohol, a certain disinhibition often sets in first, leading to euphoria. At the same time, reaction time is prolonged and coordination is impaired. At higher doses, consciousness can be reduced. Cocaine also quickly leads to euphoria, increased alertness, and activity. However, this is often already linked with restlessness and anxiety. Typically, heart rate and blood pressure increase.”
How quickly cocaine works–and the acute risks
How quickly does cocaine work?
“Of course, it always depends on the dosage, tolerance, physical constitution, body weight, and so on. With cocaine, it also depends on the method of administration. Injected, it works much faster. But even when snorted, the effect occurs relatively quickly, within minutes.”
What makes cocaine acutely dangerous?
“In general, it can cause spasms of the coronary arteries or blood vessels in general, which can lead to a heart attack. A stroke is also possible, as well as heart rhythm disturbances. Cocaine use can quickly lead to dangerous overheating of the body, known as hyperthermia, and also to seizures.”
“The size of the line says little about the risk”
Can a single line of cocaine actually trigger a heart attack?
“That is indeed possible, even if it doesn’t happen often. Especially due to the spasms of the coronary arteries and other effects on the cardiovascular system, a heart attack can occur. But the size of the line says little about the risk. It also depends on purity, additives, and individual vulnerability. And mixed use is, of course, very dangerous when other substances are involved.”
Dr. Johannes Klaus is a senior physician at the Clinic for General Psychiatry and Psychotherapy at the University Hospital Tübingen. As an addiction specialist, he heads the acute ward for addiction disorders with a focus on drug withdrawal. He also works in the substitution outpatient clinic of the university hospital. Klaus is involved in addiction research, psychedelic-assisted psychotherapy, and translational psychiatry. He is a member of several psychiatric and addiction medicine societies, including the German Society for Addiction Research and Addiction Therapy (DG-Sucht) and the German Society for Psychiatry and Psychotherapy, Psychosomatics and Neurology (DGPPN).
What can happen in the case of acute alcohol poisoning?
“If you’ve drunk too much, it can lead to vomiting, respiratory depression where the drive to breathe is dampened. Ultimately, vomit can enter the airways. Body temperature can drop–in contrast to cocaine, which can cause dangerous overheating. In acute alcohol poisoning, blood sugar levels can drop. The risk of injuries and falls is also high.”
What chronic alcohol consumption does to the body
What health damage can alcohol cause with long-term consumption?
“In the long term, the liver is damaged, among other things. It can lead to fatty liver, liver inflammation, and cirrhosis. The risk of liver cancer also increases. Furthermore, the pancreas is damaged, such as pancreatitis. Alcohol also increases the risk of various other cancers, such as those of the mouth, esophagus, and intestines. Heart damage and heart rhythm disturbances are also common with long-term alcohol consumption. Additionally, there can be damage to the peripheral nerves and the cerebellum, which can lead to coordination and gait disturbances. Such coordination disorders are also known as ataxia.”
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What chronic cocaine use does to the body
What are the long-term effects of cocaine use?
“With cocaine, it’s primarily heart-related damage, such as heart rhythm disturbances and damage to the heart muscle, leading to heart failure. Blood vessels are also damaged. Chronic cocaine use can promote the development of atherosclerosis [vascular calcification, ed.]. Strokes can also be a consequence. With nasal cocaine use, there are mucous membrane or septum damages in the nose. With years of chronic use, these damages are sometimes irreversible. With intravenous use, there are risks of infectious diseases, such as HIV or hepatitis.”
How cocaine and alcohol withdrawal differ
Looking from use to withdrawal: How does cocaine withdrawal differ from severe alcohol dependency withdrawal?
“With alcohol, withdrawal in severe dependency is potentially life-threatening because a severe physical withdrawal syndrome can develop. This is not the case for everyone–but severe alcohol withdrawal must be medically monitored and usually treated with medication. Patients often develop high blood pressure, a rapid pulse. They sweat profusely and tremble. In severe cases, this can lead to a seizure or a so-called alcohol withdrawal delirium, delirium tremens. This must be treated as an emergency. We tell our patients with severe alcohol dependency, whom we see on an outpatient basis: ‘Do not abruptly stop alcohol on your own and without medical supervision.’ You can say that alcohol withdrawal is more dangerous in terms of severe physical complications than cocaine withdrawal.”
Why does the body react so strongly when alcohol is suddenly absent?
“Chronic alcohol consumption causes the brain to counteract. The brain tries to restore balance so that one functions. When alcohol is suddenly removed, there is an overreaction that was previously ‘capped’ by alcohol. This leads to these severe physical withdrawal symptoms. Patients are therefore treated with medications that dampen the overexcitability of the nervous system.”
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“Severe alcohol withdrawal is physically much more dangerous”
What symptoms typically occur during cocaine withdrawal?
“There are at least not these severe physical withdrawal symptoms. Cocaine addicts also develop symptoms like insomnia and physical restlessness, but mainly psychological symptoms, such as a strong craving for the substance. They are irritable, easily annoyed. Of course, it also always depends on what the person brings with them.”
Is cocaine withdrawal therefore medically easier than alcohol withdrawal?
“I wouldn’t say that so generally. Psychological withdrawal symptoms can also be very distressing. But in terms of potentially life-threatening physical withdrawal complications, severe alcohol withdrawal is generally much more dangerous and requires correspondingly intensive medical monitoring.”
What psychological effects can alcohol and cocaine have?
“Both cocaine and alcohol can cause, for example, depression and anxiety disorders. Under cocaine, psychotic disorders can also occur, such as paranoia or the feeling of being watched. Psychological disorders can already exist before substance use, be exacerbated by use, or be triggered by the substances themselves.”
Was the psychological disorder there first, and did it lead to an addiction disorder? Or is the psychological disorder a consequence of the addiction disorder?
“That often can’t be answered precisely. For example, some people with ADHD use psychoactive substances as a form of self-treatment to achieve relief or states in which they feel mentally better. With alcohol, this is the case for many people with anxiety disorders because alcohol temporarily relieves anxiety, especially social anxiety. In the long term, however, substance use can exacerbate psychological complaints and promote a problematic cycle of use and increasing symptoms.”
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“A relapse does not necessarily mean the treatment has failed”
As an addiction specialist, is it frustrating for you when patients relapse and return?
“No, I wouldn’t say that. You have to see it this way: It’s a chronic disease–and the emphasis is on disease, not a character flaw. You have that in every other area too. When you treat a diabetic or patients with high blood pressure or other chronic diseases, they also keep coming back to the hospital because they have a chronic disease. Relapses or consumption events are part of the disease, and a relapse does not necessarily mean the treatment has failed.”
Why alcohol is underestimated despite its risks
Why do we underestimate the dangers of alcohol?
“I think legal is often intuitively confused with safe. Legality primarily says something about regulation and societal acceptance, but not about toxicity or addiction potential. Alcohol is normalized through our daily lives and social rituals. And often, people who already have problematic alcohol consumption shift the problem to a small group of addicts, to which they do not count themselves. They say, ‘That’s a problem for alcoholics, not me.’”
Does it also play a role that we compare our consumption with that of others?
“Yes. That’s also an individual overestimation or a false comparison standard. People say, ‘I drink less than that person.’ Or, ‘I only drink beer, I don’t drink spirits.’”