get some juices going

[ofra]

what is the meaning of this saying?

[Soup]

"This is an idiom which suggests that the body has juices that start flowing into the blood stream to stimulate activity. In truth the body has adrenaline produced to give the body a quick boost of performance." Source get juices flowing - WordReference Forums

[David L.]

When we smell food coming from the kitchen, we start to salivate (our 'mouth juices' start going), and then an aperitif with a canapé gets our digestive juices going.

We extend this into a metaphor, that something 'gets our creative juices going' that we bring to bear on tackling something which has stimulated our interest.