A character buys blackberries by the side of the road which she then eats and is thus food poisoned and vomits several times within the store (where she and the main character work) - it is very graphic.
SPOILER
She is sent to the hospital where she dies, but this is not shown in the movie. The main character tries to kill Holden by making him eat the same berries, but she changes her mind in time and makes him spit them out. He never vomits.