A questionnaire designed to measure the "milk mucus effect" was based on sensations and symptoms after drinking milk reported in interviews with 169 individuals, 70 of whom held the belief that milk produces mucus. This was used to measure responses in a randomized, double-blind trial of a flavoured UHT cow's milk drink, compared with a similarly flavoured and constituted UHT soy milk drink. The soy placebo was indistinguishable from cow's milk in a pretest of 185 individuals. Of 14 milk-mucus effect indicator variables, three showed significant increases after consumption of 300 ml of the test drink. These were "coating/lining over the mouth, throat or tongue" (39% increase), "need to swallow a lot" (31% increase) and "saliva thicker, harder to swallow than before" (42% increase). However, these increases occurred in both milk and placebo groups. It is concluded that the effect measured is not specific to cow's milk, but can be duplicated by a non-cow's milk drink with similar sensory characteristics.