Historical and Cultural References:
Greece – the color of the mythological goddess Hera, who was frequently depicted as envious or jealous.
Medieval Europe – coined the term green “green-eyed monster” of jealousy

Physiological Responses:
When people experience jealousy or envy, they may feel nauseous or sick to their stomachs. Green can refer to the color of bile.

Literary and Artistic Depictions:
Shakespeare – famously referred to it in “Othello.”

Psychological Associations:
Some psychologists suggest that the association may be partly due to the way the human brain processes emotions. Green is often associated with feelings of sickness or imbalance, which are similar to the emotional turmoil experienced during episodes of jealousy or envy.

Overall, the association between jealousy and the color green is likely a complex interplay of historical, cultural, physiological, and psychological factors, rather than a single explanation.