27 patients suffering from respiratory Allergies (asthma and/or rhinitis) were studied. They were given 25 micrograms of ketotifen/k/every 12 hours for a period of 6 months intradermal tests with house dust and Skin prick tests with D. pteronissinus, D. farinae and 7 grass mix were carried out at the start of the study, and at 3 and 6 months, at which times no significant reduction in induration and erythema was observed.