The Messenger of Allah said: "The martyrs are five: Those who die of the plague, stomach illness, drowning, being crushed, and the martyr in the cause of Allah"  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الشُّهَدَاءُ خَمْسٌ الْمَطْعُونُ وَالْمَبْطُونُ وَالْغَرِقُ وَصَاحِبُ الْهَدْمِ وَالشَّهِيدُ فِي سَبِيلِ اللَّهِ قَالَ وَفِي الْبَابِ عَنْ أَنَسٍ وَصَفْوَانَ بْنِ أُمَيَّةَ وَجَابِرِ بْنِ عَتِيكٍ وَخَالِدِ بْنِ عُرْفُطَةَ وَسُلَيْمَانَ بْنِ صُرَدٍ وَأَبِي مُوسَى وَعَائِشَةَ  

"Sulaiman bin Surad said to Khalid bin Urfutah - or, Khalid said to Sulaiman - 'Did you hear the Messenger of Allah saying: "Whoever is killed by his stomach then he will not be punished in the grave"?' One of them said to the other: "Yes."  

سَمِعْتَ رَسُولَ اللَّهِ ﷺ يَقُولُ مَنْ قَتَلَهُ بَطْنُهُ لَمْ يُعَذَّبْ فِي قَبْرِهِ فَقَالَ أَحَدُهُمَا لِصَاحِبِهِ نَعَمْ