NOTE: Use: Reaction can be postive, negative, or ambiguous. Clearly negative reaction (usually medical) goes in sense 2.
She slapped him and called him names, but he didn't react.
The judge reacted angrily to the suggestion that it hadn't been a fair trial.
Officials reacted with guarded optimism.
The government reacted by sending aid.
The kids react to everything I say.
WordNet 3.0 Sense Numbers: 1
Commentary: Syntax Is: NP1[agent[human]] REACT NP2
NOTE: usually the reaction is medical and always negative.
She reacted negatively to her new medication.
Many people react to penicillin.
If you react to kidney beans, you may also react to other members of the legume family.
He asked how she reacts to bee stings, but the child hasn't ever had one so we don't know.
WordNet 3.0 Sense Numbers: 2
Commentary: Syntax Is: NP1 REACT PP
NOTE: unlike sense 2, NP1 is non human.
Potassium reacts with water.
The chlorine reacts with the iodide to form iodine.
The drug might react to other medications the patient is taking.
WordNet 3.0 Sense Numbers: 3