Q: Is it permissible to burn or kill by water the insects that are found in houses, such as ants and cockroaches?
A: If these insects are harmful, it is permissible to kill them by insecticides and the like, not by burning.
The Prophet (peace be upon him said): Five kinds of animals are harmful and may be killed even in the Haram (all areas within the Sacred Sanctuary of Makkah): The crow, the kite, the scorpion, the mouse, and the rabid dog .According to another authentic narration, the viper was mentioned among the animals that may be killed.
This authentic Hadith reported from the Prophet (peace be upon him) indicates the permissibility of killing harmful creatures, such as ants, cockroaches, mosquitoes, flies, and predators.
However, if ants cause no harm, they are not to be killed. The Prophet (peace be upon him) prohibited killing ants, bees, hoopoes, and sparrow-hawks. This case only applies when they cause no harm.
However, when harm is perceived, they take the same ruling of the harmful animals mentioned in the Hadith. May Allah grant us success.
 Al-Bukhari, Sahih, Book on Hajj, no. 1829; Muslim, Sahih, Book on Hajj, no. 1198; Al-Tirmidhy, Sunan, Book on Hajj, no. 837; Al-Nasaiy, Sunan, Book on Hajj rituals, no. 2887; Ahmad ibn Hanbal, Musnad, vol. 6, p. 87; Al-Darimy, Sunan, Book on rituals, no. 1817.
 Abu Dawud, Sunan, Book on manners, no. 5267; Ahmad ibn Hanbal, Musnad, vol. 1, p. 332; and Al-Darimy, Sunan, Book on sacrifices, no. 1999.
What is the ruling on killing insects by electric shock, while the Prophet (peace be upon him) orders Muslims to kill and slaughter in a good way?
A: If these insects are harmful and electric shock is the only way to get rid of them, it will be permissible to use it. This will be an exceptional case of the Prophet’s order to kill in a good way, since the Prophet (peace be upon him) said, Five kinds of animals are mischief-doers and may be killed even in the precincts of Ka`bah or in the state of Ihram: They are the crow, the kite, the scorpion, the mouse, and the dog known for biting people. Also, the Prophet (peace be upon him) ordered to dip the flies [if they fall] into the water that may often cause their death.
May Allah grant us success. May peace and blessings of Allah be upon our Prophet Muhammad, his family and Companions!
The Permanent Committee for Scholarly Research and Ifta’