A randomized field trial was conducted in Tecumseh, Michigan, to test the efficacy of virucidal nasal tissues in interrupting transmission of respiratory agents in the household. In the double-blinded trial, 296 households were stratified by household size and randomly assigned to the group using treated tissues and the group using placebo tissues. Households were recruited in late August to early September 1984, and the tissues were distributed in November 1984. A 10-week influenza A(H3N2) period was identified from January 13 to March 23, 1985, although there was also evidence of rhinovirus circulation during that period. A household-level infection transmission model was used to assess the effectiveness of the virucidal tissue in the household. The model was used to estimate the secondary attack rate for the placebo and treated tissue households during the influenza A(H3N2) period. The efficacy of the treated tissue in interrupting secondary transmission was found to vary from 30.1% to 36.9%, although it could be as high as 39.4% when historical comparisons are used. However, these differences were not statistically significant. In general, the use of virucidal nasal tissue in the household appears to result in the partial interruption of transmission of influenzavirus from an infected household member to another household member during an influenza epidemic.