While 20th April may seem like an ordinary day to many, for others it marks an informal global celebration of cannabis culture. Known as “420” (pronounced four-twenty), the date has become closely associated with cannabis advocacy, awareness, and community.
At Curaleaf Clinic, we’re using the occasion to reflect on the evolving role of medical cannabis and the impact it has on tens of thousands of patients across the UK.
In this guide, we explore the meaning of 420, its origins, and its relevance for medical cannabis patients today.
At a Glance
- 420 is an informal global observance on 20th April each year, associated with cannabis culture and advocacy for legal access.
- The term “420” is widely believed to have originated in the 1970s with a group of California students, often referred to as the “Waldos”, who met at 4:20 pm to search for an abandoned cannabis crop.
- In the UK, 420 is widely associated with broader cannabis culture, but it can also be used to highlight medical cannabis, which has been legal since 2018, though awareness and access are still evolving.
- The day also plays a role in challenging stigma and promoting informed conversations around cannabis use and treatment.
What is 420?
420 is an informal day of appreciation and celebration of cannabis culture. Originating in the United States, it has since become a global phenomenon, marked each year on 20th April (4/20 in the US date format).
Each year, events and gatherings are often held to recognise progress in cannabis access, both medical and recreational, while also calling for further reform in regions where restrictions remain.
Why is it Called 420?
The origins of 420 are not definitively proven, but the term is widely believed to date back to a group of high school students in 1970s California, often referred to as the “Waldos.”
According to this account, the group heard a rumour about an abandoned cannabis crop and began meeting at
4:20 pm after school to search for it, gathering at a statue of Louis Pasteur. They referred to these meet-ups as “4:20 Louis.”
Although they never found the crop, the phrase was eventually shortened to “420” and became a codeword for cannabis-related activities, later spreading more widely through popular culture.
What does 420 Friendly Mean?
This is a phrase commonly used by those who wish to let others know that they’re welcoming towards cannabis and its consumption either recreationally, medicinally or both. It’s a way of signalling a safe and non-judgmental space for those who consume cannabis.
What does 420 Signify?
While many people associate 420 with advocacy for ending cannabis prohibition, we see it as an important opportunity to raise awareness of the barriers that still exist for patients in accessing medical cannabis. Research conducted by Curaleaf Clinic suggests that as many as 1 in 2 people remain unaware that medical cannabis is legal in the United Kingdom.
Medical cannabis patients have played a key role in driving awareness and change. At Curaleaf Clinic, we aim to build on this progress by supporting education throughout the year, raising awareness among the public through traditional and social media, and working with healthcare professionals, law enforcement, and other organisations to promote accurate, evidence-based understanding and to reduce stigma.
What is the Current Legal Status of Cannabis in the UK?
Cannabis for recreational use remains illegal in the UK. However, since 2018, medical cannabis has been legally available to eligible patients with a specialist prescription.
This change followed the UK government’s decision to move cannabis from a Schedule 1 to a Schedule 2 controlled drug, recognising its potential therapeutic applications.
While this marked an important step forward, access via the NHS remains limited, in part due to the need for further high-quality clinical evidence. However, real-world evidence (RWE) is continuing to grow, helping to build a clearer picture of how medical cannabis is used, how well it is tolerated, and the outcomes reported by patients in real-world settings.
What does 420 Mean for Medical Cannabis Patients?
For medical cannabis patients in the UK, 420 can be a moment to reflect on the role medical cannabis may play within treatment, and the progress made since its legalisation in November 2018.
It’s also a reminder that while awareness is growing, there is still more to be done to improve access and challenge misconceptions.
420 presents an opportunity to move beyond stereotypes and focus on informed, evidence-based understanding. Medical cannabis remains an area of active research, and public conversations are often shaped by mixed or misunderstood information.
As awareness grows, so too should the quality of these conversations.
For some, 420 can be a chance to learn more about medical cannabis and consider how it may relate to them or those around them. This might involve having open conversations with friends, family, or colleagues, or sharing reliable information to help build better understanding.
We also offer educational sessions for healthcare professionals, police forces, and organisations looking to improve their understanding of medical cannabis. If this is of interest, please contact us at [email protected].
If you’re at the beginning of your journey, you can also complete a free eligibility assessment to understand whether a consultation may be appropriate for you.
To learn more about the origins of 420, common myths, and what it means today, watch our video with Research Director Dr Simon Erridge.
