Draco couldn't help but wince just a bit when he watched her down that potion. It was probably store bought, meaning it was more than likely made by some half-skilled twit who decided to attempt to make his life by attempting to make dangerous potions.
Looking over at Ginny, and hopefully successfully distracting her from her question, Draco motioned to the potion vial in her hands. "Where did you get that?" he commented lightly, betting more than anything that she'd purchased it somewhere in Diagon Alley.