Shaykh Ibn Uthaymeen was asked about whether vomiting breaks wudu, and he stated that it does not.

The basis for this ruling is the principle that a person's state of purity remains valid until there is clear, authentic evidence (dalil) to prove that it has been nullified. In the case of vomiting, there is no such evidence from the Qur'an or the authentic Sunnah.

Some scholars who hold that vomiting does break wudu rely on a hadith narrated from Abu al-Darda' in which the Prophet (peace and blessings be upon him) vomited and then performed wudu. However, as Shaykh Ibn Uthaymeen explains, this hadith merely shows that the Prophet performed wudu after vomiting; it does not prove that it is obligatory (wajib) to do so. An action of the Prophet, by itself, does not establish an obligation unless accompanied by a command or other contextual evidence indicating it is required.

Other narrations that explicitly state vomiting nullifies wudu are considered to be weak (da'if) by hadith scholars and therefore cannot be used to establish a ruling.

Therefore, the original state of tahara (purity) is not broken by the act of vomiting, whether it is a small or large amount. However, if a person chooses to perform wudu after vomiting out of caution and to exit from the difference of opinion among the scholars, it is good, but it is not required of them.