Sahih Bukhari | Volume 7 | Hadith Number 610

Narrated by Ibn 'Abbas and 'Aisha
Abu Bakr kissed (the forehead of) the Prophet when he was dead. 'Aisha added: We put medicine in one side of his mouth but he started waving us not to insert the medicine into his mouth. We said, "He dislikes the medicine as a patient usually does." But when he came to his senses he said, "Did I not forbid you to put medicine (by force) in the side of my mouth?" We said, "We thought it was just because a patient usually dislikes medicine." He said, "None of those who are in the house but will be forced to take medicine in the side of his mouth while I am watching, except Al-'Abbas, for he had not witnessed your deed."