The present invention provides a therapeutic method to treat non-malignant diseases characterized by the excessive tissue growth, e.g., hyperplastic diseases, comprising administering to a mammal (e.g., human) afflicted with excessive tissue growth, an effective amount of a derivative of an indole compound of formula (I):formula (I): ##STR00001## wherein R.sup.1 is lower alkyl, (hydroxy)lower alkyl, lower alkenyl, lower alkynyl, lower cycloalkyl, phenyl, benzyl or 2-thienyl; R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are the same or different and are each hydrogen or lower alkyl; each R.sup.6 is individually hydrogen, lower alkyl, hydroxy, (hydroxy)lower alkyl, lower alkoxy, benzyloxy, lower alkanoyloxy, nitro or halo, R.sup.7 is hydrogen, lower alkyl or lower alkenyl, X is oxy and thio, Y is carbonyl, --(CH.sub.2).sub.1-3--, --(C.sub.1-C.sub.3)alkyl(CO)--, or --(CH.sub.2).sub.1-3SO.sub.2--; Z is hydroxy, lower alkoxy, (C.sub.2-C.sub.4)acyloxy, --N(R.sup.8)(R.sup.9), phenylamino, (.omega.-(4-pyridyl)(C.sub.2-C.sub.4 alkoxy), (.omega.-((R.sup.8)(R.sup.9)amino)(C.sub.2-C.sub.4 alkoxy), an amino acid ester of (.omega.-(HO)(C.sub.2-C.sub.4))alkoxy, --N(R.sup.8)CH(R.sup.8)CO.sub.2H, 1'-D-glucuronyloxy, --SO.sub.3H, --PO.sub.4H.sub.2, --N(NO)(OH), --SO.sub.2NH.sub.2, --PO(OH)(NH.sub.2), --OCH.sub.2CH.sub.2N(CH.sub.3).sub.3.sup.+, or tetrazolyl; wherein R.sup.8 and R.sup.9 are each H, (C.sub.1-C.sub.3)alkyl or together with N are a 5- or 6-membered heterocyclic ring comprising 1-3 N(R.sup.8), S or nonperoxide O; n is 0, 1, 2, or 3; wherein R.sup.8 and R.sup.9 are each H, (C.sub.1-C.sub.3)alkyl or together with N are a 5- or 6-membered heterocyclic ring comprising 1-3 N(R.sup.8), S or nonperoxide O; each alkyl or phenyl group of R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and Z is optionally substituted with 1, 2, or 3 (C.sub.1-C.sub.4)alkyl groups; or a pharmaceutically acceptable salt thereof.