Background: Two atopic patients suffering from severe allergy difficult to handle by conventional medication were given Xolair despite an IgE level <30 kU/l. Methods: Increasing dosages were given and monitored by clinical evaluation and CD-sens to clinically relevant allergens. The patients’ IgE antibody fractions were 11–14%. Results: Xolair dosages extrapolated from a recommended dose for IgE of 30–75 kU/l were adapted to the patients’ IgE body pool but had very little effect. The double dose resulted in some clinical improvement and a decrease in CD-sens. However, not until the dose was doubled again did the patients become symptom free, although 1 patient needed some additional drugs but no oral steroids. CD-sens turned negative to 5 of the 7 tested allergens. Conclusions: Xolair is most useful also in atopics with an IgE level <30 kU/l. The dose must be adjusted to the size of the IgE antibody fraction adding all non-cross-reacting, clinically relevant specificities.