Does baby vomit on clothes hinder a person from establishing prayer?
Vomit, which is mouthful and comes from a person’s stomach, is najis (ritually impure). Baby vomit is included in this ruling. In the event that a baby vomits right after he is breastfed and the milk he drank comes up, this vomit is also najis according to Hanafi school. As vomit is considered as najasat al-ghaliza (gross impurity), if it is in solid form and more than 3 gr approximately when it gets on clothes, one may not perform prayer. If it is fluid and spreads on an area as big as or bigger than a palm, one may not perform prayer. Vomit which is less than these quantities is permitted and does not hinder a person from establishing prayer. However, it is makruh to establish prayer while even that small amounts are on our clothes if we have opportunity to clean them as the spirit of prayer command this. (Ibnu’l-Humam, al-Fath, I, 202-205; Ibn Abidin, Radd al-Muhtar, I, 506, 522-526).
Source: Presidency Of Religious Affairs The Turkey, High Board of Religious Affairs FATWAS