The effectiveness of domestic and foreign dispersants was compared by Labofina and swirling flask tests. Six domestic dispersants were shown to be less effective in oil dispersion than foreign products. By Labofina test, they dispersed 6-34% of the test oil at dispersant-to-oil ratio of 0.1, while dispersed 2-22% by swirling flask test. The effectiveness of dispersants varied with the type of crude oil and decreased with increasing viscosity of oil. Dispersion linearly increased in proportion to the dispersant-to-oil ratio. It was found that the $quot;self-mix$quot; dispersant, Enersperse 700, was the most effective in dispersing various crude oils. Toxicity tests with brine shrimp Artemia were performed on 12 dispersants. Two domestic dispersants had 48-hr LC_(50)`s ranging from 5.6 to 6.6 ppm which were similar to hydrocarbon slovent-type dispersants, while three dispersant concentrates had 48-hr LC_(50)`s ranging from 24.0 to 26.2ppm.