Short answer
Pork is haram in all four schools. If you ate it by mistake or without knowing, there is no sin and no expiation: spit out what is left, rinse your mouth and move on. If you ate it knowingly, it is a major sin that needs sincere tawbah (repentance), but you are still a Muslim and your prayers remain valid.
Eating pork knowingly is haram and a major sin, but it does not take a person out of Islam unless he claims pork is lawful. Eating it by mistake carries no sin. Pork is a heavy impurity (najasa ghaliza), so the mouth, hands and dishes it touched must be washed until no trace remains.
Other madhhabs
- Shafi'i
- The pig is treated like a dog: anything wet that touched it is washed seven times, one of them with clean earth.
- Hanbali
- Agrees with the Shafi'is on washing seven times, one with earth.
- Maliki
- A living pig is not impure in itself, though its meat is haram to eat.
Explanation
The Quran names the flesh of swine as forbidden in four places, and calls it impure. The ruling covers every part of the pig and everything made from it: ham, bacon, pepperoni, lard, pork gelatin and pork-based flavourings. For the reasons behind it, read why Muslims do not eat pork.
By mistake. Allah does not hold you to account for an honest error. If you find out you ate pork, or a dish cooked with lard, there is nothing to make up and no kaffarah (expiation). Rinse your mouth, wash your hands, and be more careful about checking in future. You do not need to make yourself vomit.
On purpose. This is a major sin. The way back is tawbah: regret it, stop, and resolve not to return. Your earlier prayers and fasts are not cancelled, your nikah is not affected, and you do not need to say the shahada again, unless you believed pork was lawful, which is a matter of belief.
Forced by necessity. If a person is starving with nothing else to eat, or is forced under threat, he may eat what keeps him alive and no more. The Quran makes this exception in the same verses that forbid pork.
If pork touched your plate, pan or grill, wash it well before using it for halal food. Check unclear ingredients with the halal food checker.
The evidence
Quran, Surah Al-Baqara 2:173
إِنَّمَا حَرَّمَ عَلَيْكُمُ ٱلْمَيْتَةَ وَٱلدَّمَ وَلَحْمَ ٱلْخِنزِيرِ وَمَآ أُهِلَّ بِهِۦ لِغَيْرِ ٱللَّهِ ۖ فَمَنِ ٱضْطُرَّ غَيْرَ بَاغٍۢ وَلَا عَادٍۢ فَلَآ إِثْمَ عَلَيْهِ ۚ إِنَّ ٱللَّهَ غَفُورٌۭ رَّحِيمٌ ﴿١٧٣﴾
He has only forbidden to you dead animals, blood, the flesh of swine, and that which has been dedicated to other than Allah. But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit], there is no sin upon him. Indeed, Allah is Forgiving and Merciful.
Forbids pork and makes the exception for real necessity.
Quran, Surah Al-An'aam 6:145
قُل لَّآ أَجِدُ فِى مَآ أُوحِىَ إِلَىَّ مُحَرَّمًا عَلَىٰ طَاعِمٍۢ يَطْعَمُهُۥٓ إِلَّآ أَن يَكُونَ مَيْتَةً أَوْ دَمًۭا مَّسْفُوحًا أَوْ لَحْمَ خِنزِيرٍۢ فَإِنَّهُۥ رِجْسٌ أَوْ فِسْقًا أُهِلَّ لِغَيْرِ ٱللَّهِ بِهِۦ ۚ فَمَنِ ٱضْطُرَّ غَيْرَ بَاغٍۢ وَلَا عَادٍۢ فَإِنَّ رَبَّكَ غَفُورٌۭ رَّحِيمٌۭ ﴿١٤٥﴾
Say, "I do not find within that which was revealed to me [anything] forbidden to one who would eat it unless it be a dead animal or blood spilled out or the flesh of swine - for indeed, it is impure - or it be [that slaughtered in] disobedience, dedicated to other than Allah. But whoever is forced [by necessity], neither desiring [it] nor transgressing [its limit], then indeed, your Lord is Forgiving and Merciful."
Calls pork impure, the basis for washing what it touches.
Quran, Surah Al-Ahzaab 33:5
ٱدْعُوهُمْ لِءَابَآئِهِمْ هُوَ أَقْسَطُ عِندَ ٱللَّهِ ۚ فَإِن لَّمْ تَعْلَمُوٓا۟ ءَابَآءَهُمْ فَإِخْوَٰنُكُمْ فِى ٱلدِّينِ وَمَوَٰلِيكُمْ ۚ وَلَيْسَ عَلَيْكُمْ جُنَاحٌۭ فِيمَآ أَخْطَأْتُم بِهِۦ وَلَٰكِن مَّا تَعَمَّدَتْ قُلُوبُكُمْ ۚ وَكَانَ ٱللَّهُ غَفُورًۭا رَّحِيمًا ﴿٥﴾
Call them by [the names of] their fathers; it is more just in the sight of Allah. But if you do not know their fathers - then they are [still] your brothers in religion and those entrusted to you. And there is no blame upon you for that in which you have erred but [only for] what your hearts intended. And ever is Allah Forgiving and Merciful.
No sin for an honest mistake.
Sahih al-Bukhari 2236
Sahih... إن الله ورسوله حرم بيع الخمر والميتة والخنزير والأصنام ...
"Allah and His Messenger have forbidden the sale of wine, carrion, swine and idols."
Shows pork is forbidden so firmly that even trading in it is not allowed.
Where the ruling is recorded
- al-Hidaya, Kitab al-Taharah, chapter on impurities. The pig is impure in itself; how impurities are washed.
- Radd al-Muhtar (Ibn Abidin), Kitab al-Taharah, chapter on impurities. Washing utensils that touched heavy impurity.
This answer is pending review by the scholars on our team. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.