Objectives:
This action research aimed to examine the effectiveness of a District Health Board (DHB) intervention on the reduction of law violations of retailers and effects on tobacco access by youths.

Methods:
The study conducted in 4 districts, from 4 regions, Thailand consist of: Ban Hong District in Lamphun Province, Sam Ko District in Ang Thong Province, Chaturaphak Phiman District in Roi Et Province, and Na San District in Surat Thani Province. The target group in each district were 30-50 committee of DHB. This action research had 4 research steps. These included the steps in planning, action and observing, reflection, and the evaluation.

Results:
The main outcome measures were rate of law violation of retailers as measured through store observations (including: open display of cigarette at the point of sale, selling cigarettes in sticks, and selling cigarettes to minors) and self-reported the perceived ease of access to tobacco among secondary students. Over a sixth-months period, a diverse activities were implemented in 4 district. These included community education, retailer education, positive reinforcing for tobacco retailers who complete compliance with the laws, and anti-smoke and smoke-free environments operation in the district. The results found that the rate of law violation of retailers for all 4 districts were decreased from the pre-test at statistical significance of 0.05. And the perceived ease of access to tobacco of students for all 4 districts was significantly lower than pre-test at statistical significance of 0.05.

Conclusion(s):
This results support that the law violation of retailers and tobacco access among youths can be reduced though a DHB -engaging intervention. Therefore, the ministry of public health should develop the potential and support the budget for the DHB. in order to solve the tobacco access and use among youth in their area of responsibility.