Sayyiduna Antarah (may Allah be pleased with him) said that one day the Messenger of Allah (peace and blessings be upon him) said: "Whom do you count as a martyr among you?" We said: O Messenger of Allah, the one who is killed in the path of Allah. He (peace and blessings be upon him) said: "Then the martyrs of my Ummah would be very few. Whoever is killed in the path of Allah is a martyr; the one who dies of a disease of the belly is a martyr; the one who dies from a fall is a martyr; the woman who dies in childbirth is a martyr; and the one who drowns is a martyr." Al-Hulwani added in his narration: "And the one who dies of tuberculosis is a martyr, the one who burns to death is a martyr, and the one who dies in a foreign land is a martyr."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15252