Novel compositions of matter containing aromatic compounds and terpenoids which are present in and may preferably be derived from the plant Alpinia galanga (Zingiberaceae) show synergistic effects with respect to immunomodulation, and they significantly suppress hypersensitivity reactions. Thus they are used for preparing medicaments for these purposes and, more specifically, for the treatment or prevention of IgE mediated allergic reactions and conditions, such as asthma, allergic rhinitis, atopic eczema or anaphylaxis, and autoimmune disorders, such as Crohn's disease, ulcerative colitis, rheumatoid arthritis or psoriasis, as well as for the alleviation of pain. They can for example be formulated into pharmaceuticals, cosmetics or dietary supplements. A method of preparing such compositions from Alpinia galanga is also described.