I ate by mistake while fasting — is the fast broken?

Whoever forgets while fasting and eats or drinks, let him complete his fast — for **it was Allah who fed him and gave him drink.**

Sahih al-Bukhari 1933; Sahih Muslim 1155.

The fast is not broken. No making up, no expiation. Stop when you remember, and complete it.

And pause on that last clause: he did not call it your error — "Allah fed him", that is, it was provision, not a shortcoming.

One distinction that must stay clear

This ruling is about forgetting. Eating knowingly is a different case, with its own detail on making up the fast and, for deliberately breaking a Ramadan fast, on expiation.

And the disputed cases — water going down while rinsing, injections, inhalers — have detail among the scholars, turning on what the thing actually is. None is decided here. Describe yours to a mufti.

This is educational, not a fatwa.