Her reaction caused everyone else to look in the same direction.

The reaction caused the lady to fall off and land next to the door, where the coach driver was.

An allergic reaction to a drug or food usually causes them.

It can also be caused by an allergic reaction to food or things in the air.

Juliet had looked away quickly, in case her reaction caused comment.

The boy's reaction caused the robot to pause, but only for a moment.

Allergic reactions to food can sometimes cause serious illness and death.

More rarely, it is caused by an extreme reaction to their environment.

The oil's reaction to air causes the black color.

The above reaction immediately took place and caused the crucible to become white hot.