Abstract: Khao Yai National Park is the First National Park in
Thailand and approximately 800,000 tourists visited Khao Yai yearly.
This study aimed to identify the perception of tourists in Khao Yai
National Park according to the implementation of eco-friendly
cleansers along their leisure in the campsites. Due to tourist’s
activities in the park were affected on quality of environment;
especially on water resource. Therefore, eco-friendly cleansers were
used in campsites for tourists and restaurants during high tourist
season. The results indicated positive effects of environmental
friendly cleansers on water quality in Lam Ta Khong River, as well
as the tourist’s perception on eco-friendly cleansers.