The invention relates to a composition for storage and development of eggs from helminthic parasites, where the composition further comprises a liquid carrier having a pH value of below 7 at a temperature of from 10 C to ambient temperature. The liquid carrier can be sulphuric acid, H.sub.2SO.sub.4 with a pH in the range of from 0 to 2, and antibiotics can be added. The invention further relates to a method for treating, ameliorating, prophylactic or curative, an autoimmune or allergic disease in an individual, animal or man, using eggs being separated from the composition. The present invention also relates to methods for isolation, embryonation and preservation of eggs of helminthic parasite, and to a method for producing a pharmaceutical composition comprising a helminthic parasite preparation. The helminthic parasite eggs may be from the pig whipworm; Trichuris suis ova (TSO).