Cannabis is a plant-based drug. It usually looks like small buds of leaves, or whole or shredded green leaves, and has a strong smell. It can also look like a solid lump of dark brown or black resin or a solid, crystal-like slab.

Also known as:

  • Weed
  • Marijuana
  • Pot
  • Skunk
  • Hash
  • Bud
  • Puff
  • Resin
  • Grass
  • Dope
  • Ganja

What does cannabis look like?

  • Buds of leaves, or whole or shredded green leaves. Both of these will likely have a strong smell
  • A solid lump of dark brown or black resin
  • An oil or a solid, almost crystalline sheet or slab, known as ‘shatter’ or ‘dab’

How is cannabis taken?

  • Smoking in a ‘joint’ or ‘spliff’ (similar to a self-rolled cigarette), a pipe, or a ‘bong’, which is where smoke is bubbled through water and inhaled
  • Vaping through an e-cigarette or vape, where cannabis (or its active ingredient THC) is added to the vape liquid*
  • Dabbing, where cannabis oil or ‘shatter’ is heated to a high temperature and the vapour is inhaled
  • Eating, through adding it to foods such as cakes, teas, and gummies or lollipops

*Levels of THC in vapes can be much higher than in leaves or resin from the plant, increasing the risk of overdose. Vapes marketed as containing THC may also contain SCRAs, which can greatly increase the risk of overdose.

How can cannabis make me feel?

Cannabis can make you feel:

  • Relaxed
  • Happy
  • Calm
  • Creative
  • Paranoid
  • Anxious
  • Nauseous (vomiting or ‘throwing a whitey’)
  • Hungry (‘the munchies’)
  • Giggly
  • Unmotivated, sleepy or withdrawn

Cannabis can also:

  • Lead to sexual arousal
  • Cause your eyes become red or irritated
  • Make your mouth go very dry (‘cotton mouth’)
  • Increase your heart rate and cause changes in your blood pressure and blood sugar levels

How long do the effects of cannabis last?

It depends on several factors, including your age, weight and metabolism, what you have already taken, the purity of the drug, and the dose.

Generally speaking, the effects of smoked, vaped or inhaled cannabis products usually occur after a few minutes and usually last for around an hour. The effects of eating cannabis products usually take longer to occur.

What happens to my body if I use cannabis regularly?

Using cannabis frequently can cause:

  • Memory problems and poor concentration, which can be irreversible if you start using in your teenage years
  • Anxiety, paranoia and hallucinations, especially with heavier use
  • Impair your memory
  • A serious relapse for people with a history of psychosis
  • Increased chance of developing serious mental health problems, especially if you have a family background of mental illness and you start smoking in your teenage years
  • Increase severity of asthma or coughing and wheezing

What is in cannabis?

The two main active substances found in cannabis are Cannabidiol (CBD) and Tetrahydrocannabidiol (THC):

  • CBD is legal to produce, possess and sell. It is often sold as a natural remedy and can be found in a range of products, including drinks and skin creams

  • THC is illegal to produce, possess or sell in the UK without appropriate licensing. It is responsible for the psychoactive (mind-altering) effects of cannabis

Synthetic drugs based on cannabis - known as synthetic cannabinoids, SCRAs, and Spice - work in a similar way to cannabis, but carry a greater level of risk and can lead to significant physical harm.

More about synthetic cannabinoids

How to reduce harm while using cannabis

We recognise that some ways of using drugs carry less risk than others, and by providing information which supports people to make informed decisions, we can help people to minimise harm.

Before you start, check:

  • Is now the right time? How you’re feeling when you use cannabis can impact the effects you may experience, so consider checking in with yourself and thinking about whether now is a good time for you.

  • Do I know what I’m taking? Researching what you’re planning to take, what the effects can be and how to reduce harm can help to keep you safe. 

  • Have I contacted a friend or family member? In case you need help while you’re taking cannabis, consider telling someone your plans.

While you're using:

Start low, go slow

Strength can vary between batches, even if you take the drug regularly, starting with a small amount and waiting at least two hours before your next dose can help to reduce the risk of overdose.

Go at your own pace

Everyone responds differently to drugs - trying to keep up with others puts you at greater risk of overdosing. 

Try not to use on your own

It's best not to use cannabis if you’re on your own or if you’re in a position where there is nobody you could call for help. A buddy system - where one person takes their dose first and waits until the peak effects have worn off before the other person uses - makes it more likely that someone can help if anyone overdoses.

Try not to mix

Try and use cannabis on its own, as mixing with other drugs or alcohol can increase your risk of overdose.

Take care when smoking

Mixing cannabis with tobacco can lead to nicotine dependence and increase risk of longer-term harms, so take extra care if you smoke with tobacco. Inhaling deeply will not increase the effect of cannabis, but it could damage your lungs, so try and take small and short puffs.

Find a safe space

Where you are when you take cannabis can impact the effects you may experience, so try and find a space where you feel safe, comfortable, with people you trust.

Sip water

It’s common to get a dry mouth when using cannabis, so sipping water regularly can help.

The recovery position

The recovery position helps to prevent someone unconscious from choking on vomit. If someone is unconscious, putting them in the recovery position, getting help if needed, and staying with them will help to reduce the risk of harm.

After using cannabis:

  • Looking after and being kind to yourself is important - get plenty of sleep and rest, and try to avoid taking any other drugs to give your body time to recover

  • Refuelling will help your recovery - this includes drinking plenty of water and eating something nutritious which is soft on your stomach and not too rich

And always remember - if you’re feeling low and feel you can’t talk to a friend or family member, contact us for help through our webchat or find your local service.

What do I do if I think someone has overdosed on cannabis?

It's unusual to overdose on herbal cannabis, but if it’s taken in large amounts or is contaminated with SCRAs (spice), the effects may be extreme and can lead to overdose. 

If someone passes out or falls asleep and you can’t wake them up after using cannabis, put them in the recovery position and get help fast by calling 999, telling emergency services what you know.

Symptoms of cannabis overdose include:

  • Anxiety
  • Panic attacks 
  • Unable to think or speak clearly 
  • Changes in heart rate and blood pressure, which may lead to chest pain or heart attack
  • Vomiting
  • Hallucinations

If you suspect someone has overdosed, it’s always best to administer naloxone. Naloxone reverses the effects of opioid drugs like heroin, morphine and fentanyl. Drugs bought illicitly can contain a mixture of substances, including opioids, so use naloxone if you have it. If someone hasn’t overdosed on opioids, naloxone won’t harm them. 

You can get a naloxone kit and training on how to use it from your local WithYou service. 

More information about naloxone, including how to use it.

Cannabis withdrawal signs, symptoms, and what to do

If your body develops a tolerance to cannabis, you may feel you need to take more to get the same effects. 

You can become dependent on cannabis, and regular use can lead to physical withdrawal symptoms when you try to stop or cut back.

Withdrawal symptoms include:

  • Stopping feeling tired or hungry 
  • Experiencing sweating
  • Getting the shakes
  • Feeling sick
  • Feeling moody and irritable
  • Getting an upset stomach

If you’re dependent on cannabis, we can help you cut down safely, as stopping suddenly can lead to withdrawal complications. Find a local service.

The law around cannabis

Some people may be prescribed cannabis-based medications by a healthcare professional to treat epilepsy or other neurological conditions. 

If bought illicitly, cannabis is a Class B drug, which means it's illegal to be found carrying or using it. The legal term for this is possession. The maximum sentence for possession of a Class B drug is up to five years in prison, a fine or both. 

It’s also illegal to give away or sell cannabis. This is known as supply, and is a more serious offence than possession.  It can be considered supply if you give your friend some or share some with them, and this could get you time in prison, an unlimited fine or both.

Looking for support?

If you’re concerned about your cannabis use, or if you’re worried about someone you know, we’re WithYou. We provide free, confidential and non-judgemental support and advice. Please don’t hesitate to reach out: