<s>[INST] Why do I need to shake my puffer before using it? [/INST] 
The liquid inside your puffer is mixture of medicine and propellant (the substance that forces the spray into your lungs). The medicine droplets tend to settle separately from the propellent inside your puffer when you aren't using it.

This means that if you take a dose without shaking, you could be inhaling just the propellant and no medicine at all. The mixture settles back quickly, so you need to re-shake before each puff. Source: National Asthma Council Australia. Link: https://www.nationalasthma.org.au/understanding-asthma/faqs. Field: Lung Disease. Disease: Asthma </s>