What is a stroke?
Stroke is when an artery in the brain becomes blocked, or bleeds. This results in the blood supply being disrupted in the brain. This causes loss of function within the brain ultimately affecting things such as movement, vision and swallowing. Whilst having an immediate effect on a person, stroke can also cause long term disability affecting mobility and functionality. [1,2]
There are two types of stroke:
1. Ischaemic stroke
An ischaemic stroke is due to a sudden blockage of a blood vessel in the brain. 
2. Haemorrhagic stroke
A haemorrhagic stroke is caused by a break in the wall of a blood vessel causing blood to leak into the brain. 
How does alcohol cause stroke?
Alcohol consumption above recommended Guidelines has been linked to increase the risk of stroke. Alcohol consumption increases the risk of both ischemic and haemorrhagic strokes. [3-6] The Australian Institute of Health and Welfare advise that stroke is preventable and reducing modifiable risky behaviours, such as alcohol consumption, could prevent many stroke. 
Alcohol can increase the risk of high blood pressure.
Blood pressure is the measurement of the force blood places on blood vessel walls as it travels throughout the body. High blood pressure can cause stroke as this places extra pressure on the blood vessels. This can cause the blood vessels to weaken or breakdown, which can lead to stroke. 
When cholesterol builds up this can cause plaque to line the blood vessels. High blood pressure can cause this plaque, and blood clots, to break off the artery walls and block a brain artery causing stroke. 
Blood pressure is affected by the amount of alcohol consumed. For example, research has shown that high blood pressure is more common among people who drink more than 3 standard drinks per day. Studies have found if alcohol consumption is decreased, there was a fall in blood pressure. 
Alcohol can effect blood clotting.
Clotting is required to stop bleeding, and regularly occurs in the body. Alcohol can affect the processes required to clot the blood. The effect of alcohol on clotting can increase the risk of haemorrhagic stroke.