What Nullifies Wudu?
Anything exiting the two passages, deep sleep, loss of consciousness, and — on the view of some schools — touching the private parts directly and eating camel meat.
Answers are more useful when you can see the working, so the evidence is set out below.
The evidence
The Prophet ﷺ was asked about a man who imagines something during prayer and said he should not leave unless he hears a sound or finds an odour (Sahih al-Bukhari 137) — establishing that certainty is not lifted by doubt.
Light drowsiness while seated does not break wudu; deep sleep in which awareness is lost does.
Camel meat is established as nullifying wudu in a sahih narration (Sahih Muslim 360), a position held by the Hanbalis and by many contemporary scholars.
In practice
- Never repeat wudu on the basis of doubt alone; the hadith addresses this directly.
- Bleeding and vomiting are disputed between schools — follow your school or a scholar consistently.
- Waswasah about purity is common; the treatment is to act on the default and ignore the doubt.
None of this is complicated. The difficulty is entirely in the doing, and the doing starts with one repetition today.
Go deeper. Thousands of answers, searchable by topic and reviewed before publication, are at Islamic Q&A — qa.hisnulmuslimapp.com.
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How Do I Perform Tayammum, and When Is It Allowed?
When water is unavailable or its use would cause harm: strike clean earth with both palms once, wipe the face, then wipe the hands. It replaces both wudu and ghusl.
Do I Have to Repeat a Prayer I Prayed Without Wudu by Mistake?
Yes. Purity is a condition for the validity of the prayer, so a prayer performed without wudu is repeated once you realise — but there is no sin for the honest mistake.
Do I Need to Repeat Ghusl if I Missed a Spot?
Water must reach the entire body. If an area was genuinely missed, washing that area suffices on the view of many scholars, though some require repeating the ghusl if the sequence is deemed obligatory.
Is It Permissible to Combine Prayers While Travelling?
Yes — the majority of scholars permit combining Dhuhr with ‘Asr and Maghrib with ‘Isha while travelling, and it is authentically established from the Sunnah.