A classical Pavlovian paradigm pairing an olfactory cue with allergen challenge for a single training trial was used to produce conditioned histamine release and conditioned nasal airflow decrease in seasonal allergic rhinitis sufferers. There was no conditioned increase in subjective symptoms. Histamine release and airflow decrease showed evidence of extinction by a second test trial. A second study comparing the effects of the number of training trials showed that three training trials produced greater histamine release and airflow decrease than a single training trial, suggesting stronger effects with additional training.