Unidentified assailants lobbed a homemade grenade into a house in southern Tehran on Sunday, injuring one person in the foot, reported the official Iranian news agency, IRNA.
Witnesses told the agency that the targeted family members were known as "infamous" people in the district.
The mother, her daughter and four of her sons, aged between 18 and 24, were at home when the explosion took place.
Police are investigating the case. Such attacks are rare in the area, said the agency.
In an interview with IRNA, the local governor took a sharp snipe at the perpetrators of such "vendettas."
"Irresponsible people are not entitled to carry out wayward actions," Behnam Pour-Heidari said, adding that "police and the judicial authorities will deal with thugs legally."
Over the past three years, homemade grenades have on several occasions been thrown at private homes or shops owned by the so-called "infamous" people -Albawaba.com
