Yes, coca is a Scrabble word!
...and is worth 8 points in Scrabble, and 10 points in Words with Friends
coca
Noun
1. A South American shrub whose leaves are chewed by natives of the Andes; a source of cocaine
2. United States comedienne who starred in early television shows with Sid Caesar (1908-2001)
3. Dried leaves of the coca plant (and related plants that also contain cocaine); chewed by Andean people for their stimulating effect
What Scrabble words can I make with the letters in coca?
3 Letter Words