Driving after alcohol or drugs is just the most well-known case. The offence of endangerment under the influence of a substance also applies to other activities where a person in a state of incapacitation could endanger life, health or cause great harm. Below you will find a practical summary according to current legislation and case law as of April 2026.
Not every use of alcohol or other substances automatically constitutes a criminal offence. There is zero tolerance for drivers on the road: it is an offence to drive immediately after consuming alcohol or another addictive substance or while still under the influence of alcohol or another addictive substance. A criminal offence under Section 274 of Act No 40/2009 Coll., the Criminal Code, occurs only when a person carries out a risky activity in a state of incapacity. In the case law, the key limit for alcohol is 1.00 ‰ of alcohol in the blood, while for other addictive substances the Supreme Court has set specific serum limits. It is not necessary that an accident or injury has already occurred.
For criminal law, it is not important which pharmacological group a substance belongs to, but whether it is an addictive substance within the meaning of the law. According to Section 130 of the Criminal Code, this includes alcohol, narcotic drugs, psychotropic substances and other substances which can adversely affect the psyche, control or cognitive abilities or social behaviour. For the purposes of the Criminal Code, psychomodulatory substances and classified psychoactive substances are now also explicitly considered as addictive substances.
In practice, alcohol, cannabis, methamphetamine, amphetamine, cocaine or drugs with a depressant effect are most commonly dealt with. In the case of drugs, it is not the case that ‘if a doctor prescribes it, there cannot be a problem’. What is decisive is whether a particular person was actually in a disqualifying condition during a particular activity.
Were you charged and prosecuted? The stakes are really high and it doesn’t pay to go through the criminal process without consulting an attorney.
Under Section 274(1) of the Criminal Code, a person commits a criminal offence who carries out an occupation or other activity in a state of incapacitation brought about by the influence of an addictive substance in which he or she is likely to endanger the life or health of persons or cause substantial damage to property. The Criminal Code therefore does not deal with the mere ingestion of a substance, but only with the performance of a dangerous activity in such a state.
The most common situation is driving a motor vehicle. However, the offence does not only apply to drivers. It also applies to other hazardous activities, such as operating machinery, working at heights, driving public transport or certain medical procedures. For the qualifying offence, the law specifically highlights cases where the influence of an addictive substance is particularly dangerous, typically when driving a mass transport vehicle.
Importantly, it is an abstractly endangering offence. It is therefore not necessary that someone has already been specifically endangered or that an accident has occurred. It is enough that the activity carried out had the potential to endanger a protected interest. In 2025, the Supreme Court specifically reminded that even very short driving or a slight distance traveled does not preclude criminality.
In practice, people often mistakenly rely on the fact that they “drove only a few metres”, “re-parked the car” or “no one was hurt”. Legally, however, this alone is not enough. What is decisive is the condition precluding competence and the nature of the activity being carried out.
For drivers, the rules of Act No 361/2000 Coll., on road traffic, apply at the same time. According to Section 5(1)(f) and (g), a driver must submit to an alcohol or other addictive substance test on request and, according to Section 5(2), he must not drive after having consumed alcohol or another addictive substance or while he may still be under their influence.
It is an offence to breach this zero tolerance. Driving after alcohol or another addictive substance under Section 125c(1)(c) of the Road Traffic Act is now punishable by a fine of between CZK 7,000 and CZK 25,000 and a ban of between 6 and 18 months. Refusal to be tested is punished more severely: a fine of between CZK 25,000 and CZK 75,000 and a ban of between 18 months and 3 years.
In practice, therefore:
In the case of alcohol, the case law has long been established that a blood alcohol level of at least 1.00‰ always precludes fitness to drive. However, even a lower level does not exclude criminal liability if further evidence shows that the driver was in fact in a state of incapacitation. In borderline cases, the courts therefore also assess the driving style, the driver’s behaviour, the results of breath tests and other circumstances.
For other addictive substances, the courts are now significantly assisted by a 2020 opinion from the Supreme Court’s Criminal Division. This established that a driver’s incapacitating condition can usually be inferred from toxicological findings if the blood serum concentration reaches at least the following levels:
This is an important change in practice: it is not now necessary to automatically bring in a psychiatric expert in all cases just to have the court examine the extent of the driver’s impairment by drugs. The Supreme Court has accepted that when these levels are reached, a toxicological conclusion is usually sufficient. A psychiatric expert is mainly necessary in special cases, for example, when multiple substances are used simultaneously, when dealing with sanity or protective treatment.
In practice, a common mistake is to build a defence on the phrase ‘I felt fine’. The subjective feeling of the accused is not decisive. The court relies on a legal evaluation of the evidence, in particular measurements, readings, official records, video recordings, witness statements and expert conclusions.
The basic offence under section 274(1) of the Criminal Code is punishable by imprisonment for up to one year, a fine or a ban on activity. In traffic cases, a driving ban and a fine in addition to it are very often imposed. A Supreme Court decision from 2026 shows that even in the case of drink-driving alone without an accident, the court can impose a substantial fine and a driving ban for more than two years.
The more severe penalty, six months to three years, is available when the offender causes a crash, a traffic accident, bodily injury, major property damage, or other serious consequences, among other things. The same rate also applies if the offender commits the offence while engaged in a particularly risky activity or if he or she has been convicted or released from prison for the same offence within the last two years.
It is also worth noting that the term “substantial damage” is not loosely interpreted in criminal law. According to Article 138 of the Criminal Code, the damage is at least CZK 1 000 000. However, for the purposes of Section 274(1) itself, it is sufficient that the activity carried out was capable of causing such damage.
Tip: Have you done something illegal and you are not sure if you are criminally responsible for your actions? We have discussed when you have criminal liability and what the Criminal Code says about it in our article.
If you are stopped by the police and alcohol or another addictive substance is suspected, it is important to distinguish between two levels: misdemeanour and criminal. The mere refusal to test can have very harsh administrative consequences, so “I won’t take the test and they won’t prove anything” is usually a bad strategy.
If the police classify the matter as a suspected criminal offence, do not underestimate the first steps. It is at this stage that the bulk of the evidence is formed: breath tests, blood, reports, CCTV footage and your statement. In practice, it is usually wise to have the samples and measurements checked as soon as possible to ensure that they were taken correctly, that the timings match and that the legal qualification is appropriate to what actually happened.
The law here is not entirely “mechanical”. Particularly in lower alcohol levels or in more complex cases involving a combination of multiple substances, there may be a dispute as to just whether or not a disqualifying condition has already occurred. This is where the defense tends to be strongest.
DWI under Penal Code section 274 is not limited to driving after drinking. It is any dangerous activity performed while in a state that precludes competency and that is brought about by the influence of an addictive substance. In addition to the criminal law, drivers are also subject to zero tolerance under the Road Traffic Act, so even a lower level of impairment can constitute an offence.
In 2026, the main point is that the legal assessment is no longer based on general considerations of “impairment”. For alcohol, the 1.00‰ limit is key in case law and for other addictive substances there are specific serum limits defined by the Supreme Court. If police and expert conclusions conform to these rules, the scope for defence is usually narrower; in borderline or procedurally problematic cases, on the other hand, the defence can be very effective.
Not automatically. There is zero tolerance in traffic, so even a small amount of alcohol can be an offence. However, the offence usually requires a state of disqualification; in the case law, at least 1.00‰ of alcohol in the blood is considered a certain threshold, although exceptionally less may be sufficient if further evidence shows this.
No. Section 274 applies to any employment or other activity in which a person could endanger the life or health of persons or cause substantial damage to property. Driving a car is just the most common case.
He doesn’t have to. The offence is completed by the mere performance of the dangerous activity in a state of incapacitation. The accident or injury only adds to the seriousness and may lead to a more severe penalty.
Refusal to be examined is itself a very strictly sanctioned offence. In road traffic, it carries a fine of between CZK 25,000 and CZK 75,000 and a ban of between 18 months and 3 years.
Not always anymore. The Supreme Court has set specific serum limits for selected addictive substances; when these limits are reached, the conclusion of a condition precluding competency can usually be based on toxicological findings alone. Psychiatric expert testimony is required mainly in special or contested cases.
Yes. The basic facts already allow for a ban, a fine or a prison sentence of up to one year. In traffic matters, driving bans are very common even without an accident.
Were you charged and prosecuted? The stakes are really high and it doesn’t pay to go through the criminal process without consulting an attorney.
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