A recapitulation of the indications and contraindications for such treatment is followed by a short discussion of the different extracts now available. Here the dangers inherent in the new, highly purified extracts, especially for the inexperienced, are stressed. A short review of essential points follows for the composition of the extracts, for their dosage and concerning the importance of a sufficient duration of the treatment as well as of additional "flanking" procedures. The discussion of possible reasons for side effects, their treatment and their avoidance is followed finally by a list of possible reasons for failure of specific hyposensitization.
