Yes, MEDICINES is a Scrabble word!

Letter values in Scrabble US: M 3, E 1, D 2, I 1, C 3, I 1, N 1, E 1, S 1.

Is it a valid word?

MEDICINES is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

the branches of medical science that deal with nonsurgical techniques
(medicine) something that treats or prevents or alleviates the symptoms of disease
the learned profession that is mastered by graduate training in a medical school and that is devoted to preventing or alleviating or curing diseases and injuries
punishment for one's actions

Also: medical specialty, medicinal drug, practice of medicine.