Cannabis during work hours: what Swiss law says

TL;DR

• OR Art. 321a: employees must perform work carefully – intoxication rules that out.
• Using cannabis on breaks on company premises is also prohibited (domiciliary rights, ArG Art. 6).
• Working under the influence risks written warning, summary dismissal and personal liability.
• In safety-critical jobs (construction, driving, healthcare), a positive test alone justifies suspension.

The legal basis: OR Art. 321a

Swiss Code of Obligations requires employees to perform work “faithfully and carefully”. Working under cannabis breaches that duty objectively – regardless of how one feels.

The employer must also protect the life and health of all staff (OR Art. 328). An intoxicated colleague endangers that goal – the employer may and must intervene.

Consequences: from warning to summary dismissal

A first non-safety incident usually results in a written warning. On repeat or in sensitive jobs, a single incident justifies summary dismissal (OR Art. 337).

If an accident happens under cannabis, civil liability and insurance recourse follow – potentially personal.

Medical cannabis in the workplace

Since the legislative amendment in August 2022, medical cannabis has been medically prescribable in Switzerland without an exceptional permit from the Federal Office of Public Health (BAG). However, this facilitation for patients does not alter the fundamental obligations in the employment relationship. Even with medically justified intake, the capacity to work remains the decisive metric. Employees must not place themselves in a state that endangers themselves or others. In sectors with high hazard potential, such as construction or the transport sector, the intake of medications containing tetrahydrocannabinol can lead to temporary or permanent incapacity to work for certain activities, despite a prescription.

From the perspective of employment law, there is a duty of disclosure on the part of the employee when taking impairing medications. Although those affected do not have to inform the employer of their exact diagnosis, they must report restrictions on their capacity to work or potential safety risks. The employer, in turn, must assess within the scope of their duty of care whether the employee can be transferred to a safe workplace. There is no general ban on employment, but operational safety legally always takes precedence over the employee's individual therapy wishes.

• Medical cannabis has been medically prescribable without a BAG exceptional permit since August 2022.
• A medical prescription does not exempt an employee from the obligation of full capacity to work.
• Safety-critical activities often require the disclosure of limitations.
• Employers must look for alternative, safe tasks within the scope of their duty of care.

Drug testing in the workplace and legal boundaries

Conducting drug tests in the workplace affects the personal rights of employees in accordance with the Swiss Civil Code (ZGB). Employers may not demand urine or saliva samples arbitrarily or across the board. Such intrusions into privacy are only permissible if there is a specific legal basis, an explicit agreement in the employment contract, or an immediate threat to operational safety. Even in cases of reasonable suspicion, a test cannot be physically forced. However, if an employee persistently refuses the test, this can be considered a breach of the duty of loyalty and lead to consequences under employment law.

For sectors with special safety requirements, stricter standards apply. Here, regular or incident-based checks are often anchored in company agreements and are legally permissible. The competent supervisory authorities and the Federal Data Protection and Information Commissioner (FDPIC) emphasize that proportionality must be maintained. A test may only serve to determine the current fitness for work, but not to monitor consumption behavior during leisure time. Since THC metabolites remain detectable for a long time, the interpretation of test results in the workplace context is legally demanding.

• Systematic drug testing without a specific safety relevance violates the protection of personality rights.
• Tests generally require the consent of the employee or clear contractual regulations.
• Refusing a justified test can be considered a breach of employment contract duties.
• Test results may only assess the current fitness for work and not leisure-time behavior.

Liability and insurance coverage in the event of accidents

If an employee causes an occupational accident under the influence of cannabis, this has far-reaching consequences for insurance coverage. The Swiss Accident Insurance Fund (Suva) and private accident insurers routinely check in such cases whether gross negligence is involved. In practice, the consumption of intoxicating substances before or during working hours is almost always classified as gross negligence. This entitles insurers to drastically reduce cash benefits such as daily allowances or pensions, or in extreme cases, to deny them entirely. Although medical treatment costs are covered, the financial damage to the person concerned remains enormous.

In addition to insurance-related reductions, the person responsible faces personal liability. Under the Code of Obligations, the employee is liable for damage caused to the employer intentionally or negligently. In the case of property damage to machinery, vehicles, or buildings, this can reach existential amounts. Furthermore, criminal law applies in the event of personal injury. In the case of serious accidents, cantonal law enforcement authorities investigate for negligent bodily injury or endangerment of life. The detection of THC in the blood at the time of the accident carries significant weight in such proceedings and usually rules out a lenient judgment.

• Accidents under the influence of cannabis are classified as gross negligence by insurers.
• Suva or private insurers can massively reduce daily allowances and pensions.
• Employees are personally liable for property damage they cause while intoxicated.
• Serious accidents lead to criminal investigations by cantonal authorities.

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