react
v.v. to act or change in response to something that happens. You use this when you describe how someone behaves after hearing news or how a substance changes when mixed with another.
v. to act in response to an external stimulus or influence. Intransitive; often used to describe chemical changes or human emotional responses.
How did she react when you told her the news?
The skin may react to the new cream if you have sensitive allergies, so test a small area first.
Investors tended to react unpredictably to the central bank's announcement, causing the market to fluctuate wildly before stabilizing late in the afternoon.
From re- + act. Piecewise doublet of redact.
The verb is intransitive and typically takes the preposition 'to' before the stimulus.
He reacted the news badly.He reacted to the news badly.React is intransitive and requires the preposition 'to' before a noun phrase object.