Case histories of two asthmatic patients who are allergic to the pollen allergen of Prosopis juliflora, a perennial tree abundantly seen in Delhi and northern India, are presented. Both developed immediate (Type I) as well as late (Type III) responses to intradermal, as well as inhalation, provocation tests. Prior inhalation of disodium cromoglycate inhibited the dual asthma response to inhalation tests but did not inhibit the response to intradermal tests.