The present invention relates to 3-(heteroaryl-amino)-1,2,3,4-tetrahydro-9H-carbazole derivatives of the formula (I),wherein R1, R2 and R3 are as described in the description and their use as prostaglandin receptor modulators, most particularly as prostaglandin D2 receptor modulators, in the treatment of various prostaglandin-mediated diseases and disorders, to pharmaceutical compositions containing these compounds and to processes for their preparation.本發明係關於式(I)之3-(雜芳基-胺基)-1,2,3,4-四氫-9H-咔唑衍生物,其中R1、R2及R3係如說明書所述;及其作為前列腺素受體調節劑,最特別作為前列腺素D2受體調節劑在治療各種前列腺素介導之疾病及病症中之用途;並關於含有此等化合物之醫藥組合物及其製備方法。