Three members of a family were injured as three siblings attacked them at Gobindadhabal village in Sadar upazila on Friday for advising them not to take drugs.
The injured were identified as Md Sohrab Hawladar, 60, his daughter Helena Begum, 25, and son-in-law Rabiul, 27, of the village.
Sohrab said he asked Sumon, Masum and Shafique, sons of Afzal Talukder of the village, not to take hemp.
Being angered at the advice, they swooped on him in the morning and beat him.
His daughter and son-in-law were also injured in the attack as they came in the rescue of the elderly man.
The injured were admitted at Jhalakati Sadar Hospital.