Q: Which drug is said to be responsible for various effects on van Gogh's paintings particularly Starry Night?

Answer: Digoxin

Digoxin may cause disturbance of color vision (mostly yellow and green) called xanthopsia. It is said that Vincent van Gogh's "Yellow Period" was influenced by concurrent digitalis therapy. Digoxin may cause a "halo" around each point of light which is evident in van Gogh's Starry Night.