Via http://drinks.seriouseats.com/2013/11/info-about-chartreuse-difference-between-green-and-yellow-chartreuse-how-to-mix-with-chartreuse-cocktail-advice.html (fetched January 2016) "Yellow Chartreuse includes saffron and honey to boost the yellow color and bring down the proof"
Company Email:
"Chartreuse liqueurs are made with 130 herbs and plants distilled in wine-alcohol; only the Chartreuse monks know the names of the ingredients (it has been their trade-secret since 1737)."
Chartreuse (Yellow)
Not Vegan
This product is listed as not vegan friendly.
What the company told us
Correspondence on record, with the date of each entry.