What does alkaseltezer do to oil and water?

Alka-Seltzer contains citric acid and sodium bicarbonate, which react when dissolved in water to produce carbon dioxide gas. When added to a mixture of oil and water, the effervescence from the carbon dioxide bubbles can help to disperse the oil, temporarily breaking up the surface tension between the two immiscible liquids. However, it does not create a stable emulsion; the oil and water will eventually separate again.