Medicinal Cannabis and Evidence – What the Data Actually Show Today

Evidence also emerges beyond classical study designs 

A broad evidence base for medicinal cannabis now exists worldwide, including documented treatment pathways and extensive real-world data from cohorts involving several tens of thousands of patients. These are complemented by clinical studies, even though randomized controlled trials are particularly difficult to conduct for cannabis flowers, for example because blinding is inherently limited in inhaled applications. 

A systematic overview of international literature also shows that the evidence base is continuously expanding and spans a wide range of indications (see the COPEIA database for healthcare professionals). This is not an unusual situation. In many established therapeutic areas, care is based on a combination of studies, real-world care data and physicians’ clinical experience. Gaps in the evidence therefore do not imply a lack of efficacy but often reflect structural limitations of research. 

Real-world care data show clear therapeutic patterns 

When medicinal cannabis was introduced in 2017, the BfArM (Federal Institute for Drugs and Medical Devices) established a systematic accompanying survey in order to evaluate care in a scientific manner. The aim was to assess, on the basis of real prescribing data, how effective and meaningful its use is in practice, while at the same time creating a foundation for further research. 

The evaluation included data from around 21,000 treatments, allowing robust conclusions to be drawn about real-world care. One point is crucial, however: the accompanying survey only captures patients whose treatment was reimbursed by statutory health insurance. It therefore primarily reflects severe conditions for which reimbursement is possible. Areas of use involving less severe conditions, where medicinal cannabis is also used but often without reimbursement, are not included in these data. 

The evaluation also showed the indications in which medicinal cannabis is most commonly used: chronic pain, at 76.4 percent, was by far the most frequent reason for prescription. Around 70 percent of patients reported an improvement in quality of life, and symptom relief was documented in approximately 75 percent of cases. The accompanying survey therefore clearly shows that medicinal cannabis delivers relevant therapeutic effects in clinical practice. 

These findings have also informed the further development of the regulatory framework, for example through removing prior-approval requirements for certain specialist groups by the G-BA (Federal Joint Committee). 

Dosage form is part of the treatment decision 

Questions about evidence are often directed specifically at cannabis flowers. Yet it was precisely cannabis flowers that were made reimbursable through the 2017 reform. Inhaled and oral applications differ substantially in their pharmacokinetics, particularly with regard to onset of action, peak effect and duration of action. For many patients, inhaled use is therefore medically appropriate and indispensable. The assumption that inhaled therapies could generally be replaced by oral preparations falls short and does not reflect clinical reality. 

Prof. Dr. Kirsten R. Müller-Vahl also points this out, emphasizing that “the accompanying survey commissioned by the federal government clearly shows that cannabis flowers are overall more effective and improve quality of life more markedly than alternative finished medicinal products – with fewer adverse effects. The evidence base for oral cannabis extracts (with the exception of the finished medicinal product Sativex®) is comparable to that for cannabis flowers” (Medical Tribune, 23 March 2026). 

Research takes time and requires reliable framework conditions 

Medicinal cannabis has only been a regular part of reimbursable care in Germany for a few years. For a therapeutic field of this scale, the evidence base is therefore still developing dynamically. In addition, the regulatory environment continues to evolve. Large, long-term studies require planning certainty and considerable investment. The pace at which evidence is generated is therefore not only a scientific issue, but also a structural one. 

An evidence-based therapy still developing 

The evidence on medicinal cannabis is now broad and consistent enough to define clear areas of use and to support responsible prescribing. It includes clinical studies, extensive real-world care data and international experience. Further research will continue to refine this picture. One thing is clear: medicinal cannabis is not a therapy in an experimental stage, but an established part of medical care. Against this backdrop, the regulatory framework should also be shaped consistently on the basis of evidence and should reflect actual clinical practice. 

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