Narrated Um-Salama:

(the mother of the believers) Um Sulaim, the wife of Abu Talha, came to Allah's Messenger (ﷺ) and said, "O Allah's Messenger (ﷺ)! Verily Allah is not shy of (telling you) the truth. Is it necessary for a woman to take a bath after she has a wet dream (nocturnal sexual discharge)?" Allah's Messenger (ﷺ) replied, "Yes, if she notices a discharge."